What’s the best way to use Jonathan Loaisiga?

With the signing of Gerrit Cole, the Yankees have arguably the best top four starters in the league. Who will hold the fifth spot in the rotation, however, remains to be seen. If the season were to start right now, it would probably be J.A. Happ. But he is likely to be traded, and it would be surprising if he were on the 26-man roster come March 26. One name that may be floated out there is Jonathan Loaisiga. But is he suited to be a starter or should the Yankees harness his electric stuff as a reliever? 

Loaisiga is a four-pitch pitcher: four-seam fastball, curveball, changeup, and sinker. If he were to be transitioned into a full-time reliever, he would likely have to drop one or two of those pitches. Which one should it be?

Here is his breakdown of pitches from the 2019 season:

Pitch	Number of pitches (percent usage)
Four-seam fastball	563 (51.7%)
Curveball	337 (30.9%)
Changeup	142 (13.0%)
Sinker	48 (4.4%)

He utilizes his fastball and curveball the most, making those two the logical choices to keep as a reliever. But they aren’t his top two pitches. Going by pitch value per 100 pitches from his two years in the majors, his best pitches appear to be his curveball and his sinker (0 is league-average).

Pitch	Pitch value/100 pitches	Opposing hitters’ wRC+	Average velocity (mph)
Four-seam fastball	-0.9	189	96.6
Curveball	0.7	33	84.5
Changeup	-0.3	144	89.1
Sinker	2.6	96	96.8

As you can see, his fastball and sinker have similar velocities, so he would not lose anything on that front. He might have success becoming similar to someone else in the Yankees’ bullpen: Zack Britton. Britton is known for his sinker, and he mixes in the occasional slider as well. 

Also, take a look at opposing hitters’ wRC+ against each of Loaisiga’s pitches. Hitters have feasted on his fasted and changeup, but have fared below average against his sinker and more so his curve. 

His fastball is relatively flat. While it has life, it had 40% less horizontal break than the average fastball in 2019. Based on launch angle, he is classified as a fly-ball pitcher: 58.8 percent of the balls in play against him are line-drives or fly-balls. It could help him to harness his sinker in a home run friendly Yankee Stadium — he gave up 1.71 HR/9 in 2019. And the Yankees love strikeouts — hitters whiffed 33.2 percent of the time against him, well above the league average of 24.9 percent. 

I believe that transitioning Loaisiga to the bullpen full-time would be great for him, especially considering his position on the starting rotation depth chart. Behind the big four at the top, you have J.A. Happ (for now) and Jordan Montgomery, with Michael King, Deivi Garcia, and Clarke Schmidt knocking at the door. Loaisiga has the raw stuff to thrive in a bullpen role — he just needs to focus on his strengths.