In mid-May, I argued that the Yankees should put a little more trust in Jonathan Holder. The team seems to be agreeing with me, as they've been leaning on Holder more frequently. In the past 30 days, Holder ranks 2nd in appearances and 3rd in innings pitched among all Yankees relievers. What's more, Holder has rewarded that trust handsomely, leading the team in fWAR during that same span with an 0.00 ERA and a 25.6 K-BB%. When you've been the best pitcher on the Yankees' bullpen over 30 days, you know you're doing something right.
A huge factor in Holder's success this season is that he has decided not to give up home runs any more. He has only given up one measly dinger this season, and that came on April 6 against the Baltimore Orioles. From then on, he hasn't allowed a single homer in 16 appearances, from April 21 to June 8.
In one sense, Holder's recent homer-less streak can be described as him replicating his minor league skillset. Prior to his 2016 MLB debut, Holder was death to minor-league sluggers. From 2014 to 2016, across 219.2 innings, Holder allowed just eight homers for a HR/9 of 0.33.
In another sense, however, this is a new development for Holder, who hasn't exactly been homer-prone in his MLB career, but hasn't been effective at limiting home runs, either. Last year, in his first full season in the bigs, Holder allowed 5 home runs over 39.1 innings pitched for a HR/9 of 1.14. So what has changed between then and now?
The big change has been Holder adding a changeup and slider to his repertoire, which has done wonders for his performance in general. Back in 2017, Holder relied on three main pitches; his fastball, cutter and curveball. Though they were good pitches in their own right, Holder lacked both the fastball velocity to blow away opposing hitters and the variety of pitches needed to keep them guessing, leaving him vulnerable to the occasional homer.
Holder's results and averages by pitch type bear this out. Last year, Holder's fastball and cutter were both hit hard on contact, with hitters posting a .225 ISO against his heater and a .179 ISO against his cutter.
However, Holder has addressed those concerns by utilizing his changeup and slider this year. In addition to being effective out pitches on their own, generating whiffs and weak contact, the introduction of these new pitches has made it harder for hitters to guess what's coming next, thus having a positive effect on his fastball as well.
Those of you who are particularly vigilant may have noticed that while his fastball results have improved, his cutter is actually being hit harder this year. In fact, the sole homer that Holder allowed this year also came on a cutter. While that is indeed concerning, Holder knows this as well, which is why he's only thrown 22 cutters to this date after throwing 218 of them last year. Time will tell if the element of surprise can make Holder's cutter an effective pitch again.
In sum, Holder has been able to avoid the long ball by changing his pitch mix. The introduction of his changeup and slider has enabled him to use his fastball more effectively, while allowing him to hide his cutter, which has been hit hard of late, for a bit. In a season where the Yankees' starters have struggled to provide length and the bullpen's depth has been tested, Holder's emergence as an impact arm has been a boon for Aaron Boone. Here's hoping Holder and his new-look repertoire can keep it up.