How Jonathan Loaisiga became an elite reliever for the Yankees

The New York Yankees have one of the best bullpens in baseball. They’ve had their fair share of late-game meltdowns, but the names on the staff and the numbers paint a clear story. Of course, if you take a close look at the unit’s best performer, the name you’ll find is not one of the usual suspects.

From Aroldis Chapman to Chad Green one can see where the high expectations came from, but it’s someone else currently ranking third among relievers in WAR. That would be Jonathan Loaisiga, the 26-year-old pitcher has been nothing short of spectacular in what’s been clearly a career year, and a bright spot in what’s been an at-times tumultuous season in the Bronx.

Just look at how Loaisiga ranks amongst all qualified relievers:

Those figures can only be described as superb. Loaisiga has been excellent when it comes to limiting hard contact and free passes, with his effectiveness in those two categories only matched by a select few of the game’s best relievers. He has truly joined elite company.

But what changes has he made to make the leap this year? For a guy pumping 95-plus mph with ease, Loaisiga’s four-seam fastball got hit around quite a bit early on in his career. In fact, that vulnerable heater was probably one of his biggest issues over 2018 and 2019. Opposing hitters went 32 for 97 with 13 extra base hits against him during that stretch.

This fact prompted a shift, a pretty clear one if you take a look at his Pitch% graphic throughout his career.

As of 2019, Loaisiga began using a sinker, and he has taken it to a whole new level in 2021, throwing it 56 percent of the time, and using his four-seamer as little more than a show me pitch, throwing it less than five percent of the time.

It’s not particularly hard to understand why the sinker works better as his primary option than the four-seam fastball. It ultimately comes down to two straightforward factors: average exit velocity and launch angle.

Take a look at the divergence between his four-seamer and sinker across these two key metrics

Glance at a his four-seamer’s average launch angle, and you’ll notice that it’s hovered right in the sweet spot for hitters, in the 15-20 degree range. That will almost certainly lead to quality contact and extra bases.

The sinker on the other hand has been pounded on the ground, even more so after he began throwing it at a decent clip in 2020. We can see that in an average launch angle around negative-four degrees.

Consider that the four-seam fastball is also hit significantly harder than the sinker, and you get a recipe for disaster. Trying to be an effective major league pitcher with all of these issues surrounding your primary pitch is an uphill battle at the very least, and it helps explain why Loaisiga struggled for a while despite the apparent quality of his stuff.

Ultimately, these changes have turned the Yankees right-hander into more of a groundball pitcher, a much better fit for his profile. This is backed by his batted ball profile this year, in comparison with the past couple of seasons:

With some of the premiere arms in the pen getting older, as well as nearing free agency, it’s been great to see Jonathan Loaisiga grow into what looks like a long-term threat in the bullpen. The likes of Zack Britton and Aroldis Chapman aren’t getting any younger, but Loaisiga is on an upward trajectory, propelling the Yankee bullpen in the process.