By Leon Lifschutz | Follow me on Twitter @LeonLifschutz
After the postponement of Game one between the Boston Bruins and the Carolina Hurricanes, the two teams will potentially play back to back nights twice in their first-round series. Games one and two will be played on consecutive days and if necessary, so will game five and six.
This presents a fascinating question for the coaching staff of both teams. Should they play their starting goaltender in the back to back to games? Let’s first take a look at some theory and analytics behind the decision. We can then consider each coach’s thought process and compare the goaltending tandems for each team. Finally, we can play armchair coach.
Load management has become a topic in the sports world especially with pitch counts in baseball and limiting minutes and games for star players in the NBA. While it hasn’t been as dominant a conversation in hockey overall, it certainly has seeped in with goaltenders. Long gone are the days of Martin Brodeur starting almost every game.
In 2014 Eric Tlusky, one of the foremost hockey analytics writers, published an article analyzing how rested goalies performed versus those who were playing in back to back nights. The study, looking at data from 2011-2013, found goalies played to .912 save percentage (sv%) when rested and only a .901 sv% when not rested. This article shifted the thinking of coaches who stopped riding starters in those situations. This regular season, rarely did a goalie play on consecutive nights.
However The Athletic’s analytics guru Dom Luszczyszyn took a look at the theory this past winter arguing coaches should rethink this approach. In his study, using data from 2007 through 2019, he found a much more marginal difference than Tlusky, and in some cases, no difference, in rested versus unrested. He also points out that the talent difference between each team’s goaltender is an important factor in evaluating which option will get you the best performance.
One other item to consider, the goalie is just one player on the ice, and their numbers are impacted by the team in front of them. A rested team is more likely to perform than an unrested team.
The Thought Process
With all that in mind, what should Bruce Cassidy and Rod Brind’Amour consider as they decide how to deploy their goaltenders? Both teams have very capable backup goaltenders making this an even more challenging decision. Let’s first weigh the general pros of sticking with their starter as well as the pros of going with their backup.
Pros of sticking with your starter:
- There is a lot to be said for rhythm and confidence in hockey and the starter should be able to ride both in the playoffs.
- Putting a goalie into a pressure-packed situation who hasn’t seen game action in potentially up to two weeks may not be a recipe for success.
- Tuukka Rask is a Vezina nominee and Petr Mrazek has shown an aptitude for getting hot.
- Per Luszczyszyn, goalies do not as consistently perform worse in back to backs as originally believed.
Pros for going with your backup:
- Both Boston and Carolina were in the habit of playing Jaroslav Halak and James Reimer instead of Rask or Mrazek during the regular season.
- Mrazek did not play a single back to back. In Rask’s one back to back this year he posted a .935 sv% in game one against Arizona but a .895 sv% in game 2 against lowly Detroit.
- If your starter had a heavy workload, say an overtime period or five.
- Per Luszczyszyn, over the length of his study, he does find a slight difference between rested and unrested even if the margin is smaller than Tulsky’s original work.
An important factor in making the decision is the difference between your two netminders. Let’s take a look at each team’s tandems.
(GSAA/60 stands for goals saved above average per game)
The Bruins have a great tandem. Colleague Liz Rizzo recently discussed the duo going into the restart concluding two is better than one. Halak’s numbers are starter level on a number of teams. However, Rask’s numbers exceed the difference noted in rest versus unrested, another metric demonstrating how impressive his season was.
First of all, remember David Ayres? Yea, that was 2020, what a strange year. Reimer actually has the better numbers of the two goalies. He did so playing the second half of most back to backs and while facing a slightly higher workload.
So, we have analyzed the theory, the thought process, and the numbers. Let’s put ourselves in the coach’s hot seats.
Bruce Cassidy – Cassidy may want to consider playing Halak in game two. It’s a weird year and Rask is still recovering from an injury that has limited his ice time in training camp and even in the bubble (as did an abundance of caution over a cough). However, if a game six is necessary he should stick with his Vezina nominee Rask.
Rod Brind’Amour – The Canes coach has already deployed Reimer in a game against the Rangers, a back to back. Though his team was already up 2-0 in the series he has shown he won’t hesitate to go that direction. In his pre-series presser, he also noted that he expects the team will utilize both goalies much as they did in last year’s run to the conference finals. Brind’Amour should stick with the game plan and play Reimer in all back to back situations.
Goaltending will be an important factor in this series and the coach’s deployment could swing the series.
Statistics courtesy of naturalstattrick.com