From top to bottom, the Yankees’ bullpen has been absolutely nails at the start of 2021. Through 34 games, per FanGraphs, the Yankees (2.6) have a half-win more reliever WAR than the Mets, and almost a whole win more than any team located outside of New York’s five boroughs. The relief corps had been nearly perfect until suffering rare back-to-back losses on Thursday and Friday of last week.
As of now, Yankees are on pace for a 12.4 WAR season from their relievers. Since 2010, the Yanks themselves own the two greatest single-season reliever WAR totals, with 8.9 wins in 2017 and 8.8 wins in 2018. It’s very early, but the 2021 Yankees are currently on pace for arguably the greatest season of relief pitching in baseball history — and they aren’t even doing it on historic volume.
Still, the Yankees are just 11th in total innings pitched by relievers. While a ton of credit for the pen’s success is owed to Aroldis Chapman, and a host of other Yankee relievers having career years so far, manager Aaron Boone deserves some credit for putting them in a position to find that success.
Certainly, it helps to have Chapman, the top reliever in the majors, at his disposal. Perhaps the most dominant closer of his generation, Chapman is having the best season of his career since adding a splitter to his arsenal as a legitimate third pitch to complement his already potent fastball-slider combo. In 13 innings, Chapman has been worth a whole win on his own, has struck out 29 of the 47 batters he’s faced, and has yet to allow an earned run. Right now, he’s the only pitcher in baseball who’s thrown more than three innings and still possesses a negative FIP.
Boone’s bullpen management, like most other managers’, is rooted in a clear hierarchy of his available options. This order of operations starts and ends with Chapman’s availability. When Chapman is available, he only ever pitches the ninth inning (or later) when the Yankees are tied or winning. Although Boone’s likely to miss out on an occasional high-leverage early inning every now and again, it preserves the Yankees’ best chance at an automatic three outs for when it will undoubtedly be useful. Otherwise, a stellar outing from Chapman could be fruitlessly spoiled in a loss.
Bringing Chapman into a high-leverage situation before the ninth, or with a deficit, makes sense within the context of a single game, but could undermine Chapman’s availability for an even more contextually critical outing on the following day. Paired with Chapman’s relatively restrictive workload, it makes sense to save him for games in which he can record either a save or a win. This season, Chapman has yet to pitch on three consecutive days, and likely won’t until the playoffs — if at all.
From the outside, it appears as though Boone has his “circle of trust” — a group of relievers he’s comfortable relying on when the Yankees are tied or leading — and a group he deploys to at the very least simply eat innings when the Yankees are losing, or optimally stem the tide in order to give the team a chance at a comeback. With a starting rotation and offense that Boone clearly trusts to earn the Yankees a lead entering the late innings more often than not, it makes sense to reserve his best bullpen arms for those opportunities, ample as they may be for this winning ballclub.
Beyond smartly saving his trusted arms for the highest-leverage, winning innings, Boone uses those less reliable pitchers to eat innings in losing games. However, a couple of pitchers have proven to be so dependable in those innings that they have worked their way from one group of pitchers into the other.
For example, five of Jonathan Loaisiga’s first six appearances this season occurred after the Yankees had already forfeited the lead, and ended up losing. However, he pitched so well in those games, that seven of his next nine outings came in Yankee wins, with the team either tied or leading at the time of his entrance. Though Loaisiga’s most recent appearance was the worst of the season, as he lasted just a third of an inning while allowing four earned runs (twice as many as he had to that point all season), his change in usage before that game speaks to Boone’s willingness to adjust pitchers’ roles based on their performance.
Nick Nelson’s season to date provides an example of the inverse. While he was initially deployed on Opening Day in a particularly tight spot — a tie game with a runner on second in the top of the 10th — Boone appropriately reacted to his failure to execute on April 1st and a couple of subsequent outings by relegating him to innings-eating when the Yanks are down (and later, a demotion to Scranton).
At any given moment, Boone’s hierarchy is clearly delineated, but he has proven flexible enough to shake things up between games as necessary. Any idiot with eyes and a brain would name Chapman as the Yankees’ closer, but Boone’s excelled at reacting to the early season’s bullpen performances and rejiggering his power rankings accordingly — especially after losing two of his most trusted arms to injury right out of the gate, Zack Britton and Darren O’(every)Day.
Boone is right to recognize the magnitude of the marathon that is a 162-game season in his day-to-day restraint by bringing out the punt team when it gives the Yankees a better chance of winning the next day, and refraining from using his best arms in nigh-fruitless affairs.