The Yankees should not hesitate to go to their high-leverage relievers

On Sunday, The Yankees stole a tense win in the decider of their season-opening series against the Nationals. The opening set was filled with ups and downs for the Bombers, from a pair of Statcast-breaking Stantonian blasts to their bats going cold against a pitcher who could have been in pinstripes. The Yankees were lucky to sneak out of town taking two out of three from the reigning world champs. In addition to some sloppy defense, a key bullpen decision could have cost the Yankees the rubber match.

Trailing 1-0 after three-and-a-half innings following a decent outing from Jonathan Loaisiga, Aaron Boone brought in David Hale to face the heart of the Nationals lineup. He promptly surrendered a double and a single in the inning to give the Nationals a two-run lead. Although he escaped without further damage, the situation looked bleak as the Yankees entered the top of the fifth. Nationals starter Patrick Corbin was cruising through the Yankees lineup, having surrendered a lone single to Gleyber Torres while striking out six.

The Yankees did not have the knowledge that Nationals manager Dave Martinez would subsequently pull Corbin from the game after surrendering his first run on a solo homer to Torres in the top of the seventh. All they knew was that the opposition pitcher was borderline unhittable, and that every run they surrendered would make it that much harder to mount a comeback. With that in mind, I must disagree with the decision to call on Hale over the high-leverage arms available to Boone.

This is not a new occurrence. Last year, one of Boone’s favorite ways of describing his bullpen strategy was deploying his relievers in “lanes.” This translated to having a rather strict policy of pitching Adam Ottavino in the sixth, Tommy Kahnle the seventh, Zack Britton the eighth, and Aroldis Chapman the ninth in close winning efforts.

The major problem with this strategy is that it essentially writes off the games in which the Yankees trail by only one or two. By using one of the B-team relievers, the Yankees are in a sense conceding the game when the alternative is going to one of those high-leverage guys, who have a much better shot of keeping the game where it is. How many times did the Yankees bring in Luis Cessa, Jonathan Holder, Nestor Cortes Jr. or Stephen Tarpley in close games, and it instantly felt like a lost cause?

A critical sabermetric measure for this analysis is win expectancy. You can find a preliminary description of the metric here, however all you really need to know is that it calculates each opponent’s probability of winning the contest, given the context of the game in relation to similar situations in years past.

Roughly speaking, in the middle innings, for every additional run by which a team leads or is losing, the win expectancy shifts in the favor of the winning team by about 10-15%. Basically, if we assume that a tie game has a 50/50 win expectancy (not always the case), a one-run lead conveys a 60-65% win expectancy to the team in the lead while a two-run lead conveys a 70-80% win expectancy. This is an incredibly diluted reading of win expectancy, however for simplicity’s sake it still achieves its purpose for this article.

Applying this to the situation on Sunday, when David Hale entered the game, the Nationals had a 68.2% chance of winning. By the time Eric Thames singled Starlin Castro home to take a 2-0 advantage, the Nationals’ win expectancy stood at 78.1%. This of course was all rendered moot by Gleyber and Luke Voit’s heroics, but the Yankees may not be so lucky in future games.

FanGraphs

The Yankees have to be more flexible in the deployment of their big bullpen arms. Boone cannot be afraid to throw Chad Green in trailing by one and have him pitch multiple innings. Boone must be willing to use Tommy Kahnle or Adam Ottavino in a fireman situation to end the threat before the game gets out of hand. It is imperative to maximize the team’s probability of winning with every decision made.

The fate of this improvised season hangs in limbo. The Yankees postponed their game against the Phillies last night after the Marlins, who occupied the very clubhouse the Yankees would have been entering, saw roughly 40% of their team test positive for COVID-19. It is unclear whether this game, or any other that is affected by the virus, will be made up. Therefore in a season where no game is certain, the Yankees must do everything in their power to put themselves in a winning position every game, and a major factor in that is using their high-leverage relievers in a wider range of scenarios.