How would J.A. Happ fare out of the Yankees bullpen?

As the Yankees look to acquire another starting pitcher, what has gone largely unspoken is that one of the current members of the starting rotation would be bumped into the bullpen once reinforcements arrive. While that decision has not yet been made, it seems to be a good bet that J.A. Happ would make the transition, due to his team-worst 5.23 ERA (5.30 FIP).

It is safe to wonder, however, just how well Happ would fit in the pen. Would he be nothing more than an innings-eating long man, or does he have the skill set to be a solid middle reliever?

According to Statcast, Happ has thrown five different types of pitches this season: a four-seam fastball, a sinker, a slider, a changeup, and a curve. With the exception of the curveball, which he has only thrown 12 times this season, he has incorporated all four pitches regularly into his arsenal. Relievers, however, tend to require fewer pitches. Adam Ottavino and Zack Britton have primarily been sinker/slider pitchers, Aroldis Chapman relies on a fastball/slider combo, Tommy Kahnle uses only a fastball and a changeup, and Chad Green throws a four-seam fastball more than 75% of the time.

Unfortunately for Happ, none of his pitches this year have been truly exceptional. The only pitch that he gets whiffs on more than 29% of the time is the curveball, which is likely subject to small sample size. With a fastball that sits at about 91 mph with a spin rate of 2326, it’s not exactly a pitch that can be used to dominate out of the bullpen, even if it gains a bit of velocity in shorter outings.

None of his pitches have been of that elite nature that can be used to anchor him the same way that Chapman is anchored by his fastball and Britton by his sinker. His fastball generates an xBA of .239 but has an xSLG of .515 and has an average exit velocity of 91.8. Happ’s slider has an xBA of .223 and an xSLG of .373, but only generates whiffs 21% of the time, and his changeup has an xBA of .263, yet a .327 xSLG and 84.6 mph exit velo. For this reason, Happ needs to find a mix of pitches that he can use, rather than relying on one.

Based on the Statcast metrics, Happ would likely find his best chance of success as a fastball/slider pitcher who incorporates some changeups. None of the three pitches are elite — far from it — but there is a 7 mph difference between his fastball and breaking ball, a distance that will likely increase in relief appearances. It is this difference that Happ would have to play off of in order to find success out of the bullpen.

Unfortunately for him, however, this is a tall task. Especially considering he has not pitched in relief since he made four appearances in relief for Toronto in 2012, and he has not generally found success out of the bullpen. If he wishes to provide a boost to the Yankees down the stretch, however, he will likely need to find a way to get the most out of his stuff and reinvent himself as a relief pitcher.