Dataviz

Evaluating 2021 NHL goaltender performances with goals saved above expected

The NHL recently released the nominations for the 2021 Vezina Trophy, and the finalists include Marc-Andre Fleury of the Vegas Golden Knights, Phillip Grubauer of the Colorado Avalanche, and Andrei Vasilevskiy of the Tampa Bay Lightning. For the Vezina Trophy, the goalies are voted on by the general managers, with the winner announced during the 2021 NHL Awards.

This year, the awards presentation is a bit different, as it will occur during the semifinals or the Stanley Cup Final as per NHL.com. Evidently a few details about the awards presentations are still missing. But soon enough, the award winners will be announced and we’ll find out who takes home all the NHL hardware.

While Vezina voting—and NHL award voting in general—isn’t a perfect process, the nominees are still always deserving of the nods. However, it’s the goaltenders and skaters that get snubbed in the subjective awards categories that really bring light to whether the votes cast match public and analytic perception compared to the votes that actually count.

When the 2019–20 season came to a pause last year, I looked how goaltenders compared to one another by making a data visualisation that plotted goals saved above expected (GSAx) using numbers from Evolving-Hockey. The Western Conference gave analytical insight onto Connor Hellebuyck‘s deserved win for being an outstanding goaltender, while the Eastern Conference’s goaltenders were relatively closer to each other performance-wise when the league paused.

Goals saved above expected

So why goals saved above expected? The metric itself measures how well an individual goaltender performs when it comes to making saves or letting in goals on shots of all qualities. Expected goals work by using historical data to quantify the likelihood of real-time shots turning into goals.

With that knowledge, if a goaltender makes more stops against high-danger shots, then they will consequently have more GSAx. Similarly, if a goaltender frequently lets in goals, even from low-danger shots, then they’ll be underwater in terms of GSAx.

In short, GSAx gives a real quantifiable way to describe and evaluate goaltending performances beyond the traditional statistics of save percentage and goals against average. GSAx instead looks at every single shot a goalie faces throughout a season and tallies up all the times big saves were made or weak goals were surrendered into a single number for each individual.

Visualising GSAx

It’s simple enough to plot each goaltender’s GSAx relative to one another, but to provide additional context, goaltenders are separated by division, and each team is placed in the same order as the end-of-season standings. This gives order to the teams and helps highlight whether a team’s goaltender was highly involved in earning team wins or not.

Further, colour used to display relative workloads of each goaltender in the form of Fenwick against (unblocked shot attempts). While using shots alone would be more indicative of save percentage, Fenwick was used as it better represents overall workload, since goaltenders still react even on shots that miss or hit the post. While there may not be a perfect one-to-one relationship between Fenwick and workload, I suspect it’s still better compared to using corsi (which may overpredict workload) and shots (which may underpredict workload).

The visualisations were created with R using ggplot2 and ggrepel. All of the data is from Evolving-Hockey.com and is taken at all situations and is score-and-venue-adjusted. Let’s see how the visualisation looks for the 2020–21 season.

North Division goals saved above expected

Toronto Maple Leafs

Four goaltenders made appears for the Toronto Maple Leafs, with Jack Campbell and Frederik Andersen mirroring each other in performances despite fairly similar workloads. Campbell started the season setting an NHL record with 11 straight wins, and he was the Leaf’s best goaltender over the course of the season. Among all North Division goalies, he finished fourth in GSAx with 4.64.

As Andersen was the fourth-worst goaltender in the North in GSAx posting a lowly -11.19, he and Campbell carried most of the workload for the Leafs despite having drastically different on-ice performances. Michael Hutchinson and David Rittich appeared in a handful of games, but the both ended below water in GSAx with -1.83 and -2.25, respectively.

Edmonton Oilers

In a similar manner to the Leafs, the Edmonton Oilers saw their starters have a tale of two seasons, as Mike Smith had a fairly strong season while Mikko Koskinen struggled. Smith was one of the best goaltenders in the North, posting 7.22 GSAx, which was good for third in the division.

Koskinen, in contrast, was not so great, as he’d be one of five North Division goaltenders to let in at least 10 more goals compared to expectations with a -10.37 GSAx. Stuart Skinner appeared in one game for Edmonton, in which his GSAx was -1.36.

Winnipeg Jets

The Winnipeg Jets only started two goaltender this season, and coincidentally they were the only team in the whole league to have no goaltender below the zero mark for GSAx. Of course, there was Vezina-snub Connor Hellebuyck. He was the best goaltender in the North Division, posting a highly impressive 13.72 GSAx.

He was also by and far the busiest goaltender in the league, facing the most Fenwick out of any goaltender. To face as many shots as he did while posting the second-best GSAx, his absence on the Vezina ballot is a sore spot in the NHL Awards.

Laurent Brossoit (and any goaltender backing up Hellebuyck) would be an understudy in Winnipeg, but he was still able to post a 0.42 GSAx in 14 appearances. Looking across the league, no other team came particularly close to sharing this feat with Winnipeg, as there was always at least one goaltender that was well underwater in GSAx.

Montreal Canadiens

All three of the Montreal Canadiens’ goaltenders posted negative GSAx, with Carey Price finishing the lowest with -8.11. Jake Allen had -4.25 GSAx while having a heavier workload than Price, as he faced over 200 more Fenwick. Lastly, Cayden Primeau—despite just having four appearances—was well underwater relative to his time on ice with -4.86 GSAx.

The Canadiens would be one of two teams to make the playoffs without any goaltender posting a positive GSAx.

Calgary Flames

Similar to Montreal, all four Calgary Flames goaltenders also finished the season with negative GSAx. Jacob Markstrom did not have a great year, as he was one of the league’s busiest yet worst goaltenders. His GSAx was at an abysmal -13.22.

Before David Rittich was traded to Toronto, he posted -4.16 GSAx over 15 appearances with the Flames. While Artyom Zagidulin and Louis Domingue both appeared in just one game, they were both also negative, posting -0.96 and -1.42 GSAx, respectively.

Ottawa Senators

The Ottawa Senators had five different goalies appear in the 2020–21 season, with Filip Gustavsson being the only one to have positive GSAx with exactly 3.00. However, he only played nine games for Ottawa.

The Senators instead relied upon Matt Murray for the bulk of the season, but his -15.31 GSAx was the North’s worst performance and one of the worst in the league as well.

Marcus Hogberg didn’t have a great year either, as he had -11.84 GSAx over 14 appearances, while Anton Forsberg and Joey Daccord both floated close to zero GSAx on the negative side at -0.38 and -1.74, respectively.

Vancouver Canucks

Two very differing performances between the Vancouver Canucks’ two goalies. When Thatcher Demko was given the reins as the starter, he was up to the task. Over the course of the season, he was far better than Braden Holtby was, who should have been better too. Demko ended up with 7.82 GSAx while Holtby had -8.61.

West Division goals saved above expected

Colorado Avalanche

Having one of this year’s Vezina candidates, the Colorado Avalanche actually had fairly mediocre goaltending, all things considered. While Philipp Grubauer finds himself top-3 in Vezina voting, he didn’t have a spectacular individual season, logging 4.26 GSAx. With all due respect, him getting the nod almost had more to do with the overall play of the Avalanche.

The other three Colorado goaltenders, however, all fell below expectations, with Hunter Miska drastically at the bottom of the group with -9.33 GSAx, while Devan Dubnyk and Jonas Johansson fared better with -3.52 and -2.30 GSAx, respectively.

Vegas Golden Knights

Marc-Andre Fleury should be winning this year’s Vezina trophy. While his workload wasn’t particularly heavy, his GSAx was the best in the league by far with 19.2 in 36 appearances. Hellebuyck came a distant second, but the gap between Fleury and Hellebuyck is bigger than any other gap between any two goaltenders this past season.

Robin Lehner had a good season too, posting a respectable yet much lower 4.96 GSAx (note that it’s higher than Grubauer’s). Vegas’ main tandem ultimately won the William M. Jennings trophy for allowing the least goals league-wide with just 124.

The two other goaltenders for the Golden Knights, Oskar Dance and Logan Thompson each only had one appearance. Dance played a full game and ended up with -0.98 GSAx, while Thompson saw only eight minutes of ice time and totalled 0.15 GSAx in the seriously small sample.

Minnesota Wild

Mirroring Montreal, the Minnesota Wild were the other playoff team to have no goaltender with a positive GSAx. The tandem of Cam Talbot and Kaapo Kahkonen didn’t have a great season in the GSAx front. While Talbot didn’t fare will with -6.73 GSAx, he still found wins and benefitted from the Wild having one of the better offences in the West Division.

Meanwhile, Kahkonen had an abysmal -15.59 GSAx, but was also buoyed by the Wild’s high-scoring offence that included the offensive outburst from Calder favourite Kirill Kaprizov, coupled with very formidable depth scoring from the rest of the team.

St. Louis Blues

Jordan Binnington was one of the busier goaltenders in the league, highlighted by his bright green point. However, his performance over 42 games was not particularly outstanding by any means. He ended with 2.38 GSAx, which is fairly pedestrian among heavy-workload goaltenders. He wasn’t great, he wasn’t bad.

Ville Husso, however, did not have a great debut year after spending the past four seasons mostly in the AHL. In 17 NHL appearances, his GSAx came out to -6.62.

Arizona Coyotes

The Arizona Coyotes deployed four goaltenders this past year, with Darcy Kuemper taking just under have of the available starts. However, he and the other three—Adin Hill, Antti Raanta, and Ivan Prosvetov were all closely grouped with GSAx slightly below zero.

Prosvetov was the worst of the bunch, with an even -4.00 GSAx over 3 appearances, while the other three were even more closely bound. Hill was the best Coyote goalie with -0.45 GSAx, while Kuemper and Raanta posted -1.21 and -1.91 GSAx, respectively. Essentially, all of their three main starters were very comparable to one another.

Los Angeles Kings

The Los Angeles Kings underwent a paradigm shift in their goaltending this year—Jonathan Quick didn’t start the majority of their games. In the 22 games he did start, he wasn’t fantastic, as he totalled a GSAx of -3.24.

The Kings’ new go-to starter was instead Calvin Petersen. In 35 appearances, Petersen ended at a respectable 3.76 GSAx. Sandwiched in between Petersen and Quick was Troy Grosenick, whose two appearances actually ended up amassing him 1.52 GSAx.

San Jose Sharks

All four of the San Jose Sharks’ goaltenders ended with negative GSAx, and they did it in the exact same order of workload. Martin Jones was the busiest with more than double Devan Dubnyk’s total Fenwick against, followed by Josef Korenar and lastly by Alexei Melnichuk.

A little replacing of some words from the previous sentence and we arrive at Jones having the worst GSAx with -13.71, which was not quite double Dubnyk’s -8.47. Korenar fared better with -3.23, and lastly Melnichuk did the best with -2.63 GSAx.

Anaheim Ducks

Last in the West Division, the Anaheim Ducks used three goaltenders over the course of the season. Ryan Miller was unfortunately outright awful in his final hoorah. In just 16 appearances, Miller ended with -10.69 GSAx. He’s among a small group of goaltenders that didn’t play very much yet couldn’t make timely saves when they did play.

Jon Gibson had a busy season, appearing in 35 games, but he also stumbled in terms of GSAx with -4.49. Neither the Ducks offence offered much run support for him, nor did their defence offer much help in the backend, as the Ducks finished with the second-worst goal differential.

Anthony Stolarz, in his eight appearances, finished the season with 1.40 GSAx, being the only Ducks goaltender to end with a positive total.

Central Division goals saved above expected

Carolina Hurricanes

The Carolina Hurricanes had an interesting result. While James Reimer and Alex Nedeljkovic had very similar workloads with 22 and 23 appearances each and both Fenwick totals ranging in the 800s, Reimer was a touch below zero with -2.70 GSAx, whereas Nedeljkovic had the best GSAx total in the Central with 12.92.

Even more peculiar, Petr Mrazek tallied a whopping 10.73 GSAx in just 12 appearances. Only five goaltenders hit the 10 GSAx threshold, but to do it in such a small number of games played is really something else. For context, the other four goaltenders ranged between 23 to 45 appearances in 2020–21.

Florida Panthers

Ten-million-dollar man Sergei Bobrovsky had an abysmal season as the Florida Panthers’ busiest goaltender. In 31 games, he ended up with -10.48 GSAx. Chris Driedger had the better season in Florida, where he played the role of the backup goaltender yet played like the starter. He finished with 7.03 GSAx in 23 appearances.

Lastly, Spencer Knight had a short stint in the NHL this season, making his debut after two years in the NCAA with Boston College. In his four appearances with the Panthers, he had -1.61 GSAx.

Tampa Bay Lightning

Andrei Vasilevskiy was one of the busiest goaltenders in the Central Division, and also one of the best. With his heavy workload, he finished with 12.11 GSAx, making it the fourth straight year he’d be a finalist, which included a win in 2018–19.

As good as Vasilevskiy was, Curtis McElhinney was bad. He played in less than a third of the games Vasilevskiy did, with 12 total appearances, yet he had an appalling -13.40 GSAx. Chris Gibson was negative as well, finishing with -1.96 GSAx in his two appearances.

Nashville Predators

Another team that had their two main starters have opposing performances, the Nashville Predators had Juuse Saros taking the brunt of the work with 36 appearances. He was more than up to the task as he had a formidable 6.95 GSAx. On the other side of the spectrum, Pekka Rinne had exactly -10.00 GSAx.

In between the two, Kasimir Kaskisuo made one appearance in relief of Rinne in a game against Carolina, where he did not let in any goals in just over 15 minutes of ice time, netting him 0.35 GSAx.

Dallas Stars

The Dallas Stars only had two goaltenders play for them this year, and neither were good. Anton Khudobin had a big down year, playing well below his capabilities. In 32 appearances, he had a tragic -10.29 GSAx. For context, he had 6.15 GSAx in 30 games in 2019–20.

Jake Oettinger fared far better than his counterpart but was still negative in GSAx. In 29 appearance, he had -2.95 GSAx, which was much more digestible compared to Khudobin’s.

Chicago Blackhawks

Kevin Lankinen made his NHL debut after spending the past two seasons in the AHL and ECHL. He went straight to being the Chicago Blackhawks’ starter, appearing in 37 games. However, he wasn’t particularly good, amassing -6.57 GSAx over his debut season. He did manage to put up a save percentage of 0.909, which exactly matched his AHL save percentage from 2019–20 with the Rockford IceHogs.

Malcolm Subban wasn’t much better in his role as the backup. He finished the year with -4.49 GSAx spread over 16 appearances. Collin Delia managed to finish positive for the Blackhawks, albeit by a small margin. In six appearances, Delia totalled 0.83 GSAx.

Detroit Red Wings

The Detroit Red Wings relied mostly on Thomas Greiss this past season. Unfortunately for him, departing from the Islanders led to this season being the first time since 2014–15 he’d have a personal losing record (which was when he was still with the Penguins). Over 34 appearances, Greiss was credited with eight wins and 23 losses, eight of which came in overtime, all while totalling a paltry -6.56 GSAx.

Jonathan Bernief fared better, as he posted 1.8 GSAx over 24 appearances, and actually finished with nine wins credited to him too. Calvin Pickard‘s GSAx cratered to -5.78 despite only having six appearances.

Columbus Blue Jackets

The Columbus Blue Jackets had an awful performance from Joonas Korpisalo, as he was the worst goaltender in the Central in terms of GSAx. In 33 appearances, he had -18.72, far worse than anyone else in the division. Elvis Merzlikins had a more respectable -2.43 GSAx in a similar workload with 28 appearances in the season.

Two more goaltenders took to the net for the Blue Jackets this past year, but neither finished with positive GSAx either. Matiss Kivlenieks was at -2.02 GSAx in two appearances while Veini Vehvilainen was at -0.84 in one.

East Division goals saved above expected

Pittsburgh Penguins

The Pittsburgh Penguins utilised three goaltenders in 2020–21. Tristan Jarry was the definitive starter, but he didn’t have great goaltending performances despite winning often enough to put the Penguins first in the East by seasons’ end. He actually had -9.13 GSAx over 39 appearances, which was among the bottom of the division.

Casey DeSmith was a lot better in half the workload of Jarry’s. In 20 appearances, DeSmith tallied 3.89 GSAx, which was one of the better performances in the East. Maxime Legace started one game against Buffalo in their last regular season game, and he posted a shutout. That game netted a very solid 2.24 GSAx for Legace.

Washington Capitals

While the Washington Capitals were excited to have Henrik Lundqvist on the team, he was sidelined with a heart condition that required surgery. Instead, Vitek Vanecek made his NHL debut and took the reins as the Capitals’ starter, and he had one of the heaviest workloads in the East in doing so. In 37 appearances, he had -8.45 GSAx however, being the worst on the team in that regard. Thankfully for Washington they had the offence to make up for it.

Ilya Samsonov played in 19 games, yet he had -6.67 GSAx despite the light workload. Craig Anderson managed to be this season’s goaltender that performed closest to expectations. Over four appearances, he had -0.03 GSAx, which is about as close to zero as one can get.

Boston Bruins

The Boston Bruins had their share of goaltending injuries, which forced them to play rookies Dan Vladar and Jeremy Swayman in addition to their regular tandem of Tuukka Rask and Jaroslav Halak.

Halak was the worst of the bunch in GSAx, as he had -7.35 over 19 appearances. Vladar was next with a not so great -4.79 GSAx over 5 games played. Rask was the busiest Bruins goaltender, playing in 24 games, and he had a respectable 1.16 GSAx.

However, the Bruins should be very happy with the performance of Swayman. In 10 games, Swayman posted 4.09 GSAx to go with his seven wins and three losses.

New York Islanders

Being only one of two teams in the league with this benchmark, the New York Islanders matched the Jets in having no goalies with negative GSAx. While the Jets just sneaked in with Brossoit toeing the line, the Islanders had much more clearly positive performances from both their goalies.

Semyon Varlamov had the bulk of the Islanders’ starts, and he managed 9.55 GSAx in 36 games. Ilya Sorokin played in 22 games and had a pretty decent 2.74 GSAx to his name as well.

New York Rangers

The New York Rangers deployed three goalies in 2020–21, where Igor Shesterkin was the starter and the only one to manage positive GSAx. In 35 appearances, he had 3.97. Alexandar Georgiev and Keith Kinkaid split backup duties, and they were both lower down in GSAx; Georgiev with -3.19  in 19 games,  Kinkaid with -4.27 in nine games.

Philadelphia Flyers

Whatever happened to the Philadelphia Flyers’ goaltenders this year will need a deep dive to unravel. While Alex Lyon was mediocre with -4.77 GSAx in six appearances, it was more about what happened with Brian Elliott and Carter Hart. Spoiler: the duo owned the league’s two worst GSAx performances.

Only two goaltenders in the NHL managed to be below 20 GSAx in 2020–21. Elliott surpassed that mark with -20.50 in 30 appearances, while Hart blew right by with -24.45 in 27 games played. With the Flyers opting to split starter duties, neither of them were able to handle the responsibilities very well at all.

New Jersey Devils

The New Jersey Devils had a range of varying performances from their goaltenders. Mackenzie Blackwood was their go-to starter, but in his 35 appearances, he had -13.59 GSAx, which was among the lowest in the league.

Scott Wedgewood was a better with -5.98 GSAx over 16 games, while Aaron Dell also struggled heavily with -9.6 GSAx in just seven games. Eric Comrie, who made his sole appearance at the end of January, ended up as the only Devils goaltender with a positive GSAx with 0.28.

Buffalo Sabres

The Buffalo Sabres were the only team in the league to use six goaltenders this season—the Senators used five, but no other team used more than four.

All six Sabres were negative in GSAx, and they were all tightly ranged between -1.36 by Ukko-Pekka Luukkonen’s four appearances to -7.73 from Carter Hutton’s 13. Linus Ullmark played the most games for Buffalo, and he finished with  -2.26 GSAx in 20 appearances.

Dustin Tokarski appeared in 13 games, and he posted -6.07 GSAx, while Michael Houser and Jonas Johansson had -4.10 GSAx in four games  and -4.47 GSAx in seven games, respectively.

Best goaltending performances

Overall, there were a few standout goaltenders this past season. Five goaltenders ended with more than 10 GSAx. Based on GSAx, Fleury should win the Vezina by a large margin. However, the two runner-ups in GSAx weren’t finalists for the Vezina. Hellebuyck should have been on the ballot again with a good challenge for the trophy given that he was by far the league’s busiest goaltender, but his string of losses towards the end of the season likely cost him.

Nedeljkovic was third and Mrazek was fifth in GSAx, and both had outstanding seasons with Carolina. However, neither played enough minutes individually to really be considered for the Vezina. That leaves Vasileskiy earning the nod as the only other goaltender with more than 10 GSAx.

Grubauer was 13th in GSAx, where he was sandwiched by Campbell from the Leafs and Swayman from the Bruins. Varlamov (NYI), Demko (VAN), Smith (EDM), and Saros (NSH) all had better goaltending campaigns than Grubauer in terms of heavier workloads with better GSAx, but it’d be his 30 wins that likely cushioned his voting.

We’ll see who wins the Vezina soon enough. It should be fairly close between Fleury and Vasilevskiy if I were to guess.

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