The 2017 Yankee season was full of surprises. Aaron Judge and Aaron Hicks shocked with their emergence, the rotation was better than anyone thought, and the team itself almost went all the way to the World Series. The other notable surprise was the performance of the bullpen, which was supposed to be the team’s biggest asset.
The team ended the season in the top five in reliever fWAR, but underperformed most of their underlying statistics, like run differential and BaseRuns. A lot of that underperformance can be chalked up to the bullpen blowing up with an annoying level of frequency, especially around that West Coast and midseason dip.
The best way to look at the Yankees’ bullpen fluctuation is through FanGraphs’ Shutdowns and Meltdowns metrics. The formula is pretty simple, a “shutdown” is any time a reliever’s WPA is greater or equal to 0.06, and a “meltdown” occurs when a reliever’s WPA is equal or less than -0.06. Ideally, a team would manage at least twice as many shutdowns as they do meltdowns.
In 2017, despite a record strikeout total and such a high fWAR, the Yankees bullpen could only manage to be average in the SD/MD ratio. MLB’s average SD/MD was 1.8644, while the Yankees logged a 1.8688. Of the ten playoff teams, the Yankees ranked seventh by this ratio, ahead of the Nationals, Astros and Twins, none of whom were known for a stellar bullpen.
The problem with such a mediocre SD/MD line is that it removes elements of certainty from the game. This kind of volatility adds unnecessary pressure on the management staff as well, forcing them to make critical decisions in otherwise meaningless July games.
Don’t panic yet, though. Most of these meltdowns can be pinned on Tyler Clippard, who led the team with 11 despite being traded midseason. Jonathan Holder and Bryan Mitchell both had more meltdowns than shutdowns as well, but we can certainly expect Holder to improve based on his repertoire and Mitchell is, well, Mitchell. The very bottom of the bullpen is never going to be good.
With a full season of David Robertson and Tommy Kahnle, and another full season of use out of Chad Green, you can expect a more reliable performance in 2018. All three pieces were personally above that ideal 2 SD/MD threshold, with Green logging five times as many shutdowns.
The bullpen was full of unpleasant surprises this season, and the added stress of so many blown games may have cost Joe Girardi a contract. Looking ahead to the 2018 roster, though, expect a whole lot more stability at the end of games.