Should Preds fans be worried about Pekka Rinne?

Source: USA Today

It goes without saying that Pekka Rinne is central to the Nashville Predators' success in the upcoming playoffs, given his $7M cap hit on the Predators' $60M payroll and 93.66% 5v5 Save % this season. But something has been off with Rinne as of late, with Rinne posting a sub-.900 Save % in his last five consecutive starts. While Predators fans shouldn't point to momentum alone as a reason to be concerned with Rinne headed into the playoffs (e.g., Jonathan Quick's final two games last season were both sub-.900 Save % efforts), there has clearly been a drop-off in Rinne's play. In the below chart, I split Pekka Rinne's 2014-15 5v5 Save % (both regular and adjusted based on average shot distance) into two halves of the season - before and after his knee injury on January 15th. 

Data Source: War-on-Ice.com

Is fallout from Pekka Rinne's knee injury accounting for this recent falloff?  One could look to the unsustainable play of the Predators' skaters as a cause, but Rinne's Shots Against per 60 minutes (SA60) are nearly identical for both halves of the season (28.07 vs. 27.94). Something else is almost definitely explaining why Rinne's Save % has dropped nearly two full percentage points since returning from injury. 

Now, it should be noted that we are of course dealing with sample sizes here: 37 GP / 1,770 Min for the first half and 27 GP / 1,317 Min for the second half, respectively. It's probable that luck played some role in Rinne's early season success, and that Rinne has simply regressed back to the mean. Rinne is a career 92.87% 5v5 / 93.19% Adjusted Save % goalie dating back to 2008-09, his first full season in the league. If we boil that down to his relatively healthy 2008-09 through 2012-13 seasons, the numbers are a bit higher at 92.94% 5v5 / 93.36% Adj., as Rinne played just 24 games in his anomaly of a 2013-14 season. 

Source: War-on-Ice.com

So while Rinne's second half performance is much closer to his career average than his Vezina-worthy first half was, it's not crazy to infer that the knee injury is playing a part in Rinne's recent falloff. After all, Rinne is a butterfly style goaltender, a style that contributed to his needing hip surgery in the 2013 offseason and likely helped induce this year's knee injury given the connection between the hip and knee. Granted if you were to ask David Poile or Peter Laviolette about Rinne's health, they would tell you that the goaltender is just fine. In any case though, when trying to predict Nashville's ability to progress past the Blackhawks and beyond in this year's playoffs, we should expect Pekka Rinne's play to be closer to the second half version than the first partially due to both his career numbers and his recent injury history.

When digging deeper into Rinne's 2014-15 season, I was struck by how different one advanced metric was between the two halves. A trio of statistics recently introduced by War-on-Ice that I find intriguing is the separation of saves into high, medium and low percentage scoring areas as shown in the below graphic:

Source: War-On-Ice

When we compare the two halves of Rinne's in the below chart, it is glaringly obvious where Rinne's game has fallen off since returning from injury: Medium scoring areas. As mentioned previously, we are dealing with somewhat small sample sizes here. But when it comes to shots from the left, right and high slots and center point, Pekka Rinne is having a much harder time stopping these shots now than he was in the first half of the season:

Source: War-on-Ice.com

Now there is almost definitely some bad luck going on here when it comes to Rinne stopping Medium area shots; the question is how much? It is worth repeating that Rinne's workload has not changed too much from the first to second half of the season. The Preds continue to average around 28 SA60 and medium shot opportunities accounted for roughly one quarter of Rinne's workload in both halves of the season. As Rinne's a 93.58% Medium Save % goalie for his career, a little bit of regression was to be expected here; however, Rinne's second half is much further from his career average than the first with respect to Medium Save opportunities:

Source: War-on-Ice.com

While it's probable that Rinne's Medium Save % trends back upwards, it's worth noting that Rinne's only other season where he was this low in Medium Save % opportunities was last season's hip injury-riddled season. Furthermore, 2014-15 now ranks as Rinne's second worst season for Medium Save opportunities by a large margin after being on pace to be his best year in the statistic through 37 games. Compared to his peers, Rinne's overall Save % in the second half of the season still rates him along the lines of an average NHL goaltender such as Marc Andre Fleury or Jaroslav Halak. But among 33 goaltenders that played 1,300+ minutes this season, Ryan Miller was the only goaltender with a sub-.900% Medium Save %, placing the recent version of Rinne at the very low end of the playoff goaltending spectrum in that category.

So while we can't definitively link Rinne's drop in Medium Save % to his recent knee injury, it's worth exploring in future research whether a link can be established between lower body injuries and a drop-off in Medium Save % for goalies. In theory, medium opportunities could be where goaltender health and skill and most differentiable. After all, High Save % opportunities are largely based on goaltending fundamentals than differentiable goaltending skill and health, while Low Save % opportunities have a lot more luck involved due to the shot proximity. 

So how concerned should the Predators be? While there should be more room for optimism in Nashville than other markets due to the Laviolette-coached Predators' improved ability to drive possession through multi-shot shifts, the team should at best expect Rinne to play at his career averages. Perhaps that could be enough, as this year's Blackhawks only scored on 7.62% of shot attempts. However, Rinne's recent play (not to mention the probable return of Patrick Kane for Game 1) could very well help the Blackhawks regain their goal scoring clip of 9-10% from the previous five seasons. Whether it's a function of injury or not, Pekka Rinne's play will definitely be one of the top storylines to follow in the NHL's opening playoff rounds. 

The Niklas Bäckström Conundrum for Minnesota

Source: Winona Daily News

While researching what options the Buffalo Sabres should pursue in goal for the 2015-16 season, I started to consider why Devan Dubnyk should be a serious option for the team next season. I am probably jumping the gun on this but, after reading Kevin Woodley's article on the new technique has Dubnyk added to his game, I would consider Dubnyk to be a low cost, high upside bet to maintain his success next season. But before writing that speculative post, the likeliness that the Wild will keep Dubnyk past this season deserved it's own story - which brings us to the situation they face with their longest tenured goaltender, Niklas Backstrom.

The Wild, for their part, won't worry about the possibility of resigning Dubnyk until after the season. Potentially complicating that decision is the fact the Wild already have a combined $5.3 million committed to Darcy Kuemper and Niklas Backstrom for next season. Should Minnesota resign Dubnyk, the easy call (in theory) is to move on from the Backstrom, who is 13 years older than Kuemper and is in the midst of his third straight season with a sub .920 5v5 save %. Given goalies have been found to rapidly regress in their mid 30s, the 37-year old Backstrom's $3.4M cap hit is one that Minnesota should want to move on from, independent of whether they intend to resign Dubnyk or not.

Complicating things for Minnesota is that Backstrom has almost definitely become what Down Goes Brown calls a "negative value guy" - a player that, if Minnesota were to place on waivers tomorrow, would go unclaimed due to his current contract. Part of that is cap uncertainty - many hockey fans are well aware that Canadian dollar fluctuations and the NHLPA's unwillingness to escalate next year's Salary Cap at the expense of increasing escrow creates uncertainty in how much (if any) the cap will rise for the 2015-16 season. But most of that is because Backstrom's deal is in February 2015 is just a poor contract, one that is paying more for past performance than the future.

Wild fans that would love to test whether Backstrom is actually a negative value guy and waive him will be disappointed, as Backstrom's No Movement Clause prevents him from getting sent to Minnesota's AHL affiliate in Iowa like Josh Harding was earlier this season (though even if he were able to be waived, only $925K of Backstrom's $3.4M AAV would saved against the cap).  Also complicating the situation is Backstrom's modified No Trade Clause; though it's uncertain how many teams he has the right to block a trade to, the player's happiness in Minnesota would likely make him unlikely to waive it for a team he really doesn't want to play for - with the odds being good that teams with the cap space and willingness to take on his full deal if Minnesota were to throw in a positive asset (e.g., Buffalo) are on Backstrom's NTC list.

Among the teams that Backstrom can be traded to, an opposing GM would demand Minnesota hold most, if not all, of the 50% cap hit ($1.7M) GMs are allowed to retain in trades under the current CBA. Veteran backup goalies with no trade protection generally don't fetch much of a return, such as Peter Budaj this past fall (for Eric Tangradi) and Ilya Bryzgalov last season (for a Minnesota 4th round pick). As Backstrom's Modified NTC gives him the some ability to control his own destiny if he's traded, the Budaj and Bryzgalov returns seem like a best case scenario for the Wild.

One last option the team could explore is buying out the remaining year of Backstrom's contract this summer. While CapGeek's closure in January keeps me from being able to link the buyout calculator math from that site, we can manually calculate the buyout as I did in a post a few weeks ago when talking about what Buffalo should do with Cody Hodgson. Those curious on the instructions for calculating a buyout should refer to this Blueshirt Banter post, but the penalty for buying out Backstrom can be calculated as such:

• Per Spotrac, Backstrom is due $4M in Year 3 (2015-16) of his 3-Year, $10.25M deal (AAV of $3.417M). The buyout amount is 2/3 of the remaining salary ($2.667M). That $2.667M buyout amount is spread evenly over the double the remaining length of the deal - i.e., the next two years, so $1.333M each for the 2015-16 and 2016-17 seasons.
• For 2015-16, the $1.333M buyout amount is subtracted from Backstrom's $4M salary to calculate a "cap savings" of $2.667M. The cap savings are then subtracted then out of the AAV that gives us a $750k cap penalty ($3.417M - $2.667M) for the 2015-16 season.
• For 2016-2017, the cap penalty is the $1.33M buyout amount.

Given the near zero value the Wild are likely to get back for Backstrom in a trade (even with holding salary), the cost of buying out Backstrom is potentially easier to stomach. Due to his contract being slightly backloaded, Backstrom's cap penalty is actually lower next season than the year that exceeds his original deal. But therein lies the issue with buying out Backstrom. Consider the players the Wild need to resign in the summer of 2015:

• UFAs: Kyle Brodziak, Keith Ballard, Nate Prosser, Ryan Carter, Stu Bickell
• RFAs: Mikael Granlund, Marco Scandella, Erik Haula

Though RFAs Granlund and Scandella are due for sizable raises from their sub respective $900K and $1.025M deals, both are in line for more modest raises than, say, Cody Hodgson in Buffalo. Additionally, all of Minnesota's UFAs should be affordable to resign and/or readily replaceable. As it is, Minnesota has just $56.6M tied up in 15 players for 2015-16 - including Backstrom. In fact, a Backstrom buyout saves Minnesota $2.667M in AAV for 2015-16, versus a trade saving Minnesota as little as $1.67M in addition to the asset the Wild likely have to give up to trade the salary. As a result, those extra buyout savings can be allocated to resign their upcoming FAs and/or another goaltender - say, Dubnyk - with higher upside than Backstrom. 

Where the real issue potentially comes is the the 2016-17 season, when the $1.333M buyout charge will have to be added to a Wild cap that is projected to consist of the elevated Granlund and Scandella salaries, Dubnyk's (or another goalie's) cap hit, any 2015/2016 UFA signings, and four more important RFAs Minnesota will be in line to resign that summer: Jared Spurgeon, Matthew Dumba, Jason Zucker and Darcy Kuemper. In translation - buying out Backstrom may hurt the 2016-17 cap more than keeping or trading Backstrom at a reduced rate hurts the 2015-16 cap.  

Source: USA Today

Alternatively, the Wild could decide to keep Backstrom for next season, perhaps due to a mix of loyalty to the nine year Wild veteran and wishful thinking that Backstrom can regain his form as part of a platoon. Minnesota could then borrow a page from the 2013 Canucks' playbook and trade away the goaltender in waiting (24-year old Kuemper) for a good asset as opposed to trading away the veteran goaltender with a toxic contract (Backstrom) in a salary dump. This option is fairly appealing for the Wild if they have internally given up on Kuemper. As to whether they should trade Kuemper: though his .905 5v5 save % through 29 GP this season is concerning given the success Dubnyk has had behind the same Minnesota defense, the Wild do not have much in the goaltending pipeline beyond Kuemper, who still has the athleticism and upside to be a full-time starter in Minnesota. The Wild only have to look to Dubnyk to see that, with some work on his technique this summer, Kuemper's development can be brought back on track.

Of course, another scenario is Dubnyk's 11-2-1 run in Minnesota this past month is not only unsustainable, but the inevitable drop off in his play is so severe that the Wild decide to walk away from him altogether come June. But even in that case, the decision for the Wild next year should be what other goalie they should acquire over the summer to compete with Backstrom and/or Kuemper for the starter's job next season. Because whether it's Dubnyk or someone else, Mike Yeo and the Wild deserve better than going into next season with the horrid Kuemper / Backstrom tandem that nearly sunk the Wild's 2014-15 season before a rejuvenated Devan Dubnyk brought the team back from the brink.

Rationalizing a Cody Hodgson Buyout

Source: The Vancouver Province

In this week's 30 Thoughts (Point 4), Elliott Friedman was the first I've seen raise possibility of a Cody Hodgson buyout this summer though the idea had previously been suggested on the SabresNoise blog. At first, the idea seemed a surprising given Hodgson being one of the few Sabres on long term deals with offensive upside (e.g., leading the Sabres in points for the 2013-14 season, albeit with just 20 goals and 24 assists in 72 GP). But given his abysmal stat line (2G and 6A in 51GP, tied with Torrey Mitchell for 13th on the team as of February 8th) and mediocre possession numbers (0% Corsi Rel on a league worse 37.1% 5v5 Corsi team, despite having a relatively higher number of offensive zone starts and weaker quality of competition) more than halfway into the 2014-15 season, it is an idea that has become fun to explore as evidenced by recent blogs in favor of and against jettisoning Hodgson. Being a healthy scratch against the Islanders tonight (his third time this season) should only fuel the talk of a Hodgson buyout between now and the start of free agency. 

Source: War-On-Ice; Minimum 200 Minutes Played as of February 8th

First off, with CapGeek & its handy buyout calculator out of business, we will have to do some manual math to calculate why a Hodgson buyout could be an enticing proposition for Buffalo this summer. A 2010 post from Blueshirt Banter has a straight forward bulleted list of how a buyout is calculated, and the first bullet point was the main reason Friedman had highlighted a Hodgson buyout as a real possibility: a player under 26 can be bought out for 1/3 of his remaining salary vs 2/3 of the remaining salary for a player over 26. With Hodgson turning 25 in February, the direct cost of buying out Hodgson significantly raises from this upcoming offseason to the next. 

Prior to the start of the 2013-14 season, Hodgson signed a 6 year, $25.5M extension, working out to a $4.25M AAV. Unlike the kind of front loaded deals that we are used to seeing older players sign, Hodgson's deal was back loaded such that his actual salary was $3M in Year 1 (2013-14), increasing $0.5M every season until he is scheduled to make $5.5M in Year 6 (2018-19). As a result, the Sabres would be on the hook for buying out 1/3 of the remaining $19M in salary he's owed ($6.3M total) as opposed to the remaining total AAV. Should the Sabres hypothetically wait until the summer of 2016, the Sabres would be on the hook for 2/3 of the remaining $15M ($10M total):

Source: CapGeek data via the Wayback Machine 

Sabres Owner Terry Pegula may very well not want GM Tim Murray to spend another $6M this summer for someone to not play in Buffalo following last summer's compliance buyouts of Ville Leino and Christian Ehrhoff, who are respectively being paid $7.33M and $12M over the next dozen or so years to not play professional hockey in Buffalo. However, let's assume that Mr. Pegula would indeed drill another oil well to buyout Hodgson's remaining albatross of a contract if that is what it takes to win a Cup in Buffalo. So how much would a buyout affect Buffalo's salary cap? As shown in the below table, the $6.3M Hodgson is owed will be spread over twice the remaining 4 years of the contract (working out to $0.79M per season through 2022-23). For the years within the contract, the cap hit is equal to the difference in the $4.25M AAV and the "cap savings", which is the annual difference in Hodgson's salary and the $0.79M owed to him (e.g., in 2015-16, the cap saving are $3.21M, which is $4M in salary minus the $0.79M cost). For a summer 2015 buyout, the years that extend beyond the contract are just equal to the $0.79M owed Hodgson:

Source: CapGeek data; black data represents cap penalties, red data represents cap credits

Now contrast the cap hits vs. 2016. From 2016-17 to 2021-22, the buyout would cost an additional $0.88M, a small but not insignificant salary cap penalty for the Sabres to incur. The team's current rebuild means it will be awhile before they would/should realistically want to spend to the cap ceiling; additionally, Buffalo's willingness to spend to cap ceiling since Mr. Pegula's purchase of the team versus the internal cap the team had set under Tom Golisano gives the Sabres more flexibility to incur a buyout cost if that's what the franchise sees fit. An escalating salary cap - which has been predicted by James Mirtle to hit $100 million by the time the current CBA expires in 2022 - would further decrease the relative cost of having Hodgson's bought out salary on the books. 

However, the Sabres almost certainly expect to be contenders by the time Hodgson is due a new contract, let alone any years the bought out contract would sit on the cap. How high the cap will rise over the time frame also remains more in flux now than at the end of 2013 due to a couple different reasons. First off, the NHLPA will remain hesitant to inflate the salary cap at the expense of increasing escrow, the amount of salary the NHL holds out of player paychecks, as explained in the same Friedman piece from this week. Secondly, a strong American dollar multiple years into the future directly affects the value of revenues collected in Canada and would place downward pressure on the salary cap rising in future years. To a lesser extent, a strong American dollar also weakens the profitability of future global events the NHL is pushing forward as revenue drivers in coming years, including the return of the World Cup of Hockey (to take place in Toronto and Montreal in 2016) and a proposed "Ryder Cup" in European markets. 

But back to the main issue at hand: what is Tim Murray to do with Cody Hodgson? The cap savings from moving from Hodgson this year vs. waiting are tempting. But should the Sabres jettison one of the few players with pure scoring talent on their roster, particularly one who under the right system could finally reach the potential to play the two-way game so desired in today's NHL? 

To Hodgson's credit, this season has been a confluence of bad factors that many players of his tier would also falter under. For starters, Hodgson's 2 goals can largely be explained by his 3.0% overall shooting percentage (3.6% 5v5) thus far in the 2014-15 season, significantly below his career average of 10.8%. Part of it is also Hodgson is shooting the puck at a lower clip this season. With just 67 shots through 51 GP, Hodgson's 1.3 shots per game would be the lowest of his career as a full time NHLer (he had 9 shots over 8 games as an AHL call-up for Vancouver during the 2010-11 regular season). Another issue has also been the subtraction of Thomas Vanek and Jason Pominville from the roster, who Hodgson played the majority of his relatively successful 15G 19A lockout-shortened 2013 season. Adjusting for zone starts during that 2013 season, Hodgson was better at driving possession when he was on the ice with Vanek and Pominville than without. Conversely, Vanek and Pominville also played with Hodgson than without, a credit to Hodgson's ability to be more than just a passenger with Top 6 talent. 

Replacing Vanek and Pominville on Hodgson's line has primarily been Chris Stewart (a soon to be ex-Sabre largely more renowned for his size than for his ability to score or drive possession) and a revolving door of wingers and centers, as Hodgson himself has spent time this season alternating between the wing and center. Following the expected exodus of forwards such as Stewart, Torrey Mitchell and Drew Stafford at the trade deadline, Hodgson could get a chance to close the season out on a higher note by getting more playing time back in the Top 6 of the lineup. As it is, Hodgson is one of the "unluckier" players on Buffalo, with a PDO of 97.6 due to the Sabres scoring just 5% with him on the ice at 5v5 (vs. 8.1% 5v5 overall).  

In my own opinion, there's enough evidence to believe that if Hodgson were to be placed with better line mates and was having better luck shooting the puck, we'd more so be talking about what Buffalo could possibly trade Hodgson for than whether he should be bought out or not, which I ultimately don't believe the Sabres should do. However, the question is whether Buffalo should keep him long-term, and I am inclined to lead towards no on this. Though Hodgson can again be a 20 goal scorer when playing with quality line mates, Coach Ted Nolan seems insistent on burying Hodgson on the bottom 6. Perhaps part of that is bad defense, but if the Sabres are to trade Hodgson they will need to showcase him with Top 6 forwards to convince teams with a need for scoring wingers that he is worth the majority of his $4.25M AAV in a trade with the Sabres.

Speaking of trading Hodgson, as it's inconceivable seeing a team taking on 100% of Hodgson's contract for a few reasons. First off, another team would almost certainly require sending back a similarly bad or even worse contract to Buffalo if they were to acquire Hodgson at full cost, making the proposition of buying out Hodgson more appealing. As they did with the Vanek and Pominville trade, the Sabres would almost certainly offer to hold salary to maximize the return they get for trading Hodgson. Secondly, Hodgson's back-loaded contract structure makes him slightly more desirable to big market teams than small market teams, who are more likely to prefer back loaded deals with lower AAVs than salary that help them cost effectively reach the cap floor. But since many big market teams are so close the cap ceiling as is, prospective Hodgson acquires will want to acquire him at the lowest AAV possible. 

At this moment in time, Hodgson is probably what you would consider to be a "negative value guy" as defined by Sean "Down Goes Brown" McIndoe - a guy who, if Buffalo were to place on waivers tomorrow would go unclaimed at a $4.25M AAV given this season's play. Yet part of that is due to teams' ability to acquire guys at lower AAVs than the deals they were originally signed to thanks to the new CBA. Trading Hodgson within the next year or two at a pro-rated salary after his luck will have taken a turn for the better provides Buffalo the best chance at turning him into another asset. Even if an eventual Hodgson trade turns out to be a salary dump, any salary Buffalo holds back in a trade would come off the books at the end of Hodgson's current contract in 2019 versus 2022 or 2023 - a significantly more advantageous year to be free of dead money given where Buffalo hopes to be in their current rebuild.

So in conclusion, Murray's decision on Hodgson's future should be when/if to trade Hodgson as opposed to when/if to buy him out, and part of that will involve getting Ted Nolan to bring Hodgson back into the Top 6 of the lineup where he will be most productive (and hence most valuable). Sure, Hodgson is most likely not the Top 6 center the Sabres hoped they acquired in exchange for Zack Kassian at the 2012 trade dealine. Yet despite his current scoring struggles, below average faceoff numbers and reputation as a soft, "injury prone" player, at a lower AAV there's definitely still a place for Hodgson in the NHL as a depth scoring forward, like he was his rookie season in Vancouver. That place is just not in the bottom 6 of a rebuilding Sabres team.

Sloan Recap: Oh, Brian Burke

Source: National Post

Last week, I wrote at length about how hockey could learn a thing or two from basketball in using optic-tracking cameras and wearable devices to capture new data streams. At MIT's Sloan Sports Analytics Conference (SSAC) last weekend, MLB announced that Milwaukee, Minnesota and the New York Mets would be debuting field-tracking cameras to help quantify player positioning and movement from multiple directions, with all stadiums having the cameras installed by 2015.

Mark Newman's article on MLB.com does an excellent job of breaking down the implications for baseball, and many of these would be directly applicable to hockey. When it comes to quantifying general athletic attributes such as speed, positioning, and hand-eye, optic-tracking cameras are helpful towards more accurately quantifying all sports. The potential for optic-tracking video cameras was introduced at Sloan's hockey analytics panel by Eric Tulsky of SB Nation who, as always, fought the good fight for advancing the discussion and application of statistical analysis in hockey.

Alas, Brian Burke showed up and, well, this oral history from a few attending media members should tell you how it went (note: some strong language thanks to Brian Burke).

And we're off. Burke asked immediately if his view on analytics has changed. Says no immediately: "I think it's an eyeballs business."
— Craig Custance (@CraigCustance) February 28, 2014

Burke: "Still an eyeballs sport. We see things that even video scouting doesn't show, like how a player responds after a coach yelling."
— Frank Seravalli (@DNFlyers) February 28, 2014

Burke: "If you're on a horseshit team, you're probably a minus player." #SSAC14
— Frank Seravalli (@DNFlyers) February 28, 2014

Jesus. The moderator just cites Bergeron as a guy who analytics don't value right. He leads the league in Corsi Rel. #ssac14
— Blake Murphy (@BlakeMurphyODC) February 28, 2014

Lots on intangibles and character talk on the hockey analytics panel at the biggest sports analytics conference in the country.
— Derek Jedamski (@D_Jedamski) February 28, 2014

In defending Ovechkin, Don Fishman says AO's ability to score clutch goals isn't always appreciated: "That's the thing analytics misses."
— Craig Custance (@CraigCustance) February 28, 2014

"Cap not difficult to manage. Just simple math." - Brian Burke #SSAC14
— Derek Jedamski (@D_Jedamski) February 28, 2014

Tulsky really has not had much of an opportunity to speak. The only guy with a true analytics back ground (as far as I know)
— Derek Jedamski (@D_Jedamski) February 28, 2014

Burke: "If you ever want to see statistics misused, sit in on an salary arbitration in the NHL. The creativity is staggering." #SSAC14
— Craig Custance (@CraigCustance) February 28, 2014

Burke: "I would never do Moneyball because it's boring... I have to entertain people." #SSAC14
— Craig Custance (@CraigCustance) February 28, 2014

I can't even keep up.
— Craig Custance (@CraigCustance) February 28, 2014

Asked what needs to change, @BSH_EricT basically BEGS for NHL SportVu. #ssac14
— Blake Murphy (@BlakeMurphyODC) February 28, 2014

Moderator lobs Burke a softball to counter Tulsky and say coaches could give you what Tulsky admits he couldnt (finer details). Burke agrees
— Derek Jedamski (@D_Jedamski) February 28, 2014

Burke talks about learning character of a player, talks to his family, "his grade school teachers" before drafting a guy.
— Derek Jedamski (@D_Jedamski) February 28, 2014

"Let's not confuse analytics for basic arithmatic" - Guy on hockey analytics panel at biggest sports analytics conference (Burke)
— Derek Jedamski (@D_Jedamski) February 28, 2014

This is endlessly entertaining for me. I just feel bad for anyone who travelled to Boston hoping to actually learn about hockey analytics.
— 67Sound (@67sound) February 28, 2014

Burke: "I don't like the shootout It's a circus stunt- like NFL games being decided by QB throwing balls through tires. It's horseshit."
— Frank Seravalli (@DNFlyers) February 28, 2014

Burke says there is a movement to change overtime but shootout is here to stay. Believes 3-4 playoff races will be determined by shootouts.
— Craig Custance (@CraigCustance) February 28, 2014

Burke thinks NHL rinks are too small. Wants to go to Boston University 91-foot rink.
— Craig Custance (@CraigCustance) February 28, 2014

Also, we might be getting off track here.
— Craig Custance (@CraigCustance) February 28, 2014

Unfortunately, there is actually very little analytics talk right now for hockey at #SSAC14. Convo has been steered away from analytics.
— Frank Seravalli (@DNFlyers) February 28, 2014

DataPuck: A Primer to Hockey’s Place in the World of Big Data

At next weekend’s MIT Sloan Sports Analytics Conference, research papers on the “datafication” of baseball and basketball will show how those respective sports are utilizing new data streams and techniques to deliver new analytical insights on evaluating player performance. Hockey fans should not expect the same.

"Tilted Ice", the only hockey paper to be accepted for Sloan, will presents an insightful look on how teams (although not individual players) change on-ice behavior in third periods of contests. There will additionally be a panel on Friday dubbed “Hockey Analytics: Out of the Ice Age” that will discuss the use of analytical judgement for individual player evaluation. If contrasted with recent developments in basketball, hockey is still a ways away from a warm period. 

Take, for example, EPV (short for Expected Possession Value), a methodology to be presented in Sloan  research paper "POINTWISE" that utilizes optical tracking data from the SportVU cameras the NBA installed earlier this year in collaboration with STATS LLC to evaluate player performance and decision making. Another Sloan 2014 research paper, "The Hot Hand", additionally utilizes the NBA's optical tracking data to evaluate a different metric of performance (streakiness). While the use of optical tracking cameras in the NBA is old news, the NBA's D-League recently announced a few weeks ago that four teams will be piloting the use of small, wearable devices for tracking player movement and other bio-related indicators.

   

For a hockey fan, the NBA’s utilization of "big data" collection and analysis techniques is a woeful reminder of just how far behind hockey analytics are relative to its peers. How to define big data? For tech companies, the phrase is generally used to describe data whose size exceeds the CPU memory of traditional databases and analytics tools – a bit of a silly definition, since this just means today’s big data analysis tools are tomorrow’s data analysis tools.  Perhaps a better definition comes from the 2013 Financial Times Book of the Year finalist "Big Data”, which suggests the revolution is not behind the tools themselves. While increasingly sophisticated business intelligence and analytics tools help to make big data analysis more economically feasible for businesses and individual statisticians alike, the real revolution is in the world’s shifts towards capturing far more streams of data – all the data – and empirically analyzing it. 

The NBA’s pioneering usage of machine-generated data (as opposed to human-generated data from sources such as emails, photos, tweets etc.) highlights what I believe will be the most common way sports will expand to harness new data sources. While POINTWISE and The Hot Hand will spark discussions at Sloan around additional use cases for basketball, the papers should additionally spark discussions around the use of optic-tracking camera in other fluid, fast-paced sports - i.e., hockey. 

The Next Wave of Hockey Datafication

If I were a betting man, the hockey analytics panel at Sloan will only briefly touch on the idea and potential of optic-tracking cameras for the NHL and hockey, should the question be raised. Based on the panel description, the discussion will more so focus on expanding adoption and usage of currently hockey analytics tools (such as Corsi, Fenwick and PDO helped popularized by Behind the Net and Extra Skater) among hockey decision makers. However, the usage of machine-generated data to create the hockey equivalent of EPV model with 'big data' is an intriguing idea for the NHL to theoretically pilot.

The idea of an EPV isn't new. At Sloan last year, a research paper presented a methodology, dubbed Total Hockey Rating (THoR), that aimed to evaluate NHL players based on the idea that each player contributed to the probability of that a goal is scored and prevented. Of course, the study that suggested Tyler Kennedy was the third most valuable player in the NHL from 2010-2012 should raise some eyebrows. While THoR helps to push forward hockey analytics by presenting sound judgment in its methodology, its usage of hits methodology reflects the real weakness facing hockey analytics – the stats that are easily measurable don’t necessarily reflect what a player's true value could be away from when and where a notable hockey play happens that machine-oriented data could easily replicate.

Like in POINTWISE, an EPV algorithm leveraging machine-oriented data could be devised for hockey that tracks the probability of scoring for every moment a player enters the offensive zone (or if a player has the puck any zone if Ondrej Pavelec is in net). EPV additionally presents a framework to calculate the value of “entry passes, dribble drives and double-teams” in basketball; in hockey, the same could be done for evaluating pieces of hockey strategy be it dump and chases, shot selection and line chemistry (I’m looking your way, Chris Kunitz). One could imagine a world where a trail blazing hockey coach plug players into a zone model similar to the half court model provided by POINTWISE co-author Kirk Goldsberry in this Grantland piece and, leveraging billions of rows of machine, calculate success probabilities of player selection and formation on power plays and penalty kills. Models for the antithesis of EPV – perhaps expected defensive value – could be developed to identify players best at limiting high percentage shot opportunities and creating turnovers. Not only will machine-generated data help overcome the need to use Corsi and Fenwick as proxies for puck possession, but it will additionally help more accurately identify which players correlated with both possession and takeaway ability (not to mention turnover liability).  

While the potential of machine-oriented data to help devise coaching strategy and support GMs in player transaction decisions has seemingly unlimited potential, its application by coaches "on the fly" seems unpractical given the need for reaction prompt decision making (i.e., the home team has an 8 second limit on making line changes in between whistles; the away team has just 5 seconds). The infiltration of iPads and tablets behind hockey benches, as has become common place among baseball managers such as Joe Maddon, is probably around the corner. However, their use will probably be reserved for drawing plays with styluses and streaming instant video replay than plugging in variables to calculate probabilities, which sports such as baseball and football have greater use for given the longer lag time in between plays. 

Data derived from wearable devices as the D-League is testing would additionally help hockey organizations derive new insights on players, given that models to evaluate speed, acceleration, endurance and other bio-related data in basketball are directly transferable to hockey. As noted in Zach Lowe’s article, the collection of bio-related data would raise concerns for the union, with any sort of application of optic-tracking cameras or wearable devices to be meticulously negotiated by Donald Fehr and the NHLPA. However, the discussion of wearable devices, and optic-tracking video cameras for that matter, are still in the future without further buy of more sophisticated analytics among hockey decision makers in general.

Hockey Analytics Today

For the hockey analytics world, the good news is that acceptance and adoption is gradually coming in the sport even if it is lagging its peers. Most notably, the Penguins detailed at a predictive analytics conference in Toronto last year how they’re working with the Sports Analytics Institute to create a player evaluation system leveraging player location and shot probabilities to create predictive systems for goals for/against and lifetime value. The model's first application in practice came in 2011, when the Penguins acquired James Neal from the Dallas Stars in what is arguably one of the most lopsided trades in recent memory. In January, the New Jersey Devils threw their hat into the analytics ring with the announcement of hiring of a Director of Analytics that will report directly to Lou Lamoriello (although it remains to be seen how or if the old-school Lamoriello will leverage the person ultimately hired for the position).

While possession stats are useful to help hockey fans better evaluate their favorite NHL teams and players (with their application in lower AHL, NCAA and junior levels providing a new opportunity to scout players), it’s still early days in the datafication of hockey and its acceptance in hockey circles. 'Intangibles’, ever a point of contention in social media fights between analytical and old school hockey types, should highlight an opportunity for hockey analytics to create new models in favor of arguing with old school thought. As papers such as the Hot Hand suggest, not every old notion should be dismissed where "advanced statistics" fail to exhibit any correlation. Rather, all that could be needed is more data to suggest a correlation does exist.

Take New York City for example, which has embraced big data analysis techniques to identify illegal, over occupancy buildings that are more prone to deaths in the case of fires  Highlighted in the aforementioned "Big Data" book, New York City’s first “Director of Analytics” Mike Flowers highlights an exchange with a senior fire chief concerning an apartment with multiple red flags based on his team's algorithm, with the senior fire chief's gut claiming a building was likely passable because the brick exterior was new. Instead of brushing off the old guard’s hunch and sticking with the team's existing algorithm, Flowers’ team took note of the senior chief’s insight and quantified brick exterior investments through city building permits.

Ultimately, the datafication of hockey presents an exciting opportunity for blogs like this one to grow with the infusion of hockey related data both on and off ice, and maybe get a hockey decision maker or two to listen along the way. While currently available analytics help to deliver new deeper insights for evaluating player and team performance than +/-, it is important to realize their limitations and develop methodologies to better analyze "the coolest game on Earth". 

At the very least, it's more entertaining than watching the Sabres for the foreseeable future.