The Yankees bullpen has been as good as advertised

The Yankees have a pretty solid recent history of excellent bullpens. Last season, they assembled the three-headed monster of Aroldis Chapman, Dellin Betances, and Andrew Miller. Not long before, Mariano Rivera and David Robertson anchored a great relief corps. Robertson, Rivera, and converted-starter Phil Hughes dominated in relief as a huge part of the 2009 World Series Champions.

When Robertson was acquired along with Tommy Kahnle (and Todd Frazier) a month ago, it was clear the Yankees were committing to creating another outstanding bullpen. Both Roberston and Kahnle were in the midst of fine seasons worthy of late-inning roles, and they were added to a bullpen that already included the flame-throwing Betances and Chapman, as well as Adam Warren, the highly effective swingman, and Chad Green, who has popped up to become a dominant reliever almost out of nowhere.

Chapman has had a fairly awful past month, blowing saves, yielding back-breaking home runs to 20-year-old rookies, and generally giving Yankee fans heart attacks whenever he steps on the mound. His struggles have been high-profile and concerning, but even in spite of their closer's poor play, the Yankees' newly-assembled bullpen has been as excellent as advertised.

When the Yankees tossed Robertson and Kahnle in the mix, the upshot was obvious; manager Joe Girardi now had an incredibly deep arsenal to play around with. He could deploy his bevy of relief aces in unconventional ways, bringing in dominant pitchers in the middle innings regularly if he wanted, and making any close, late-inning affair a frightening proposition for the Yankees' opponent.

In this case, what was promised has come to fruition. The Yankees' bullpen has been easily tops in the league, and that’s with their highest paid member going through a terrible stretch. Since the trade with the White Sox on July 18th, here's the Yankees' bullpen's ranks across the league:

Tops in the class across nearly every major category. That .245 wOBA stems from a suffocating opposing slash line of .181/.256/.303. In fact, the Yankees' 1st place ranks here may even undersell the dominance of their relievers. The distant second-best ERA over that span belonged the Cardinals at 3.07. The next-best strikeout rate was over three points lower at 28.8%. The next-lowest wOBA was thirteen points worse. Not only have the Yankees been the best, they have been the best by daylight, the Usain Bolt (pre-2017) of relief pitching.

Betances has a 0.62 ERA that span. Robertson has struck out 21 batters in 14.2 innings with a 1.23 ERA. Kahnle has a 1.54 ERA with 15 strikeouts in 11.2 innings. Green has an eye-popping 25 strikeouts in 14.2 innings. The numbers are staggering.

Yet perhaps just as encouraging as the pure numbers has been how Girardi has been able to use his relievers. I wrote last year how even with three relief aces at his disposable, Girardi and the Yankees were still pretty conservative in deploying their aces, sticking rigidly to a 7th-8th-9th inning structure with Betances-Miller-Chapman. With even more toys to play with, Girardi has simply been forced to use his relievers in more unorthodox ways.

Betances has appeared in every inning from the sixth to the ninth. Kahnle has appeared in the sixth inning four times since coming to New York, after making precisely zero such appearances with Chicago. Robertson has appeared as early as the sixth twice, after having never appeared earlier than the eighth across three years with Chicago.

Green has regularly been entering in the fourth (!) and fifth innings since the trade in a fireman role, averaging seven batters faced per appearance since July 19th. Green has been one of baseball's best relievers, and he's coming into games in the fourth inning and sticking around for one or two or three frames. That's terrifying.

This isn't to say that Girardi has unlocked some new bullpen approach, the way Terry Francona seemed to last year in using Miller in highly creative ways. It's just that Girardi's hand has been forced; he simply has so many incredible relievers, he has literally no choice other than to go to a relief ace when it's the fifth inning and the starter is in trouble.

It's not always that things work out as planned, but a month in, the Yankees' bullpen has worked exactly has advertised. It has been the bullpen that was promised. These relief aces probably can't quite keep up this level of dominance, but it's very reasonable to expect them to continue to be the best in the league. And with the Yankees on track for a playoff spot, a bullpen this deep is starting to loom as a potentially devastating postseason weapon.

Stats through games on 8/17