The Yankees have long been fans of Jonathan Loaisiga. After being released by the Giants in 2015, he signed with the Bronx Bombers. Tommy John surgery delayed his development, and he finally made his major league debut in 2018.

While Loaisiga had shown flashes of what he could be in the past, this year seems to be the year that he’s finally put it all together. In 9 appearances to start the season (13.1 innings), he has allowed only 2 runs, with 13 strikeouts to just 1 walk. He’s become an increasingly important arm in a dominant Yankee bullpen.

So, how has he done it?

From the Rotation to the ‘Pen

Loaisiga, like nearly every reliever, began his career as a starter. In his rookie campaign, he started 4 games for the Yankees, with relative success. He struggled a bit when he appeared out of the bullpen in September, but even then, one bad outing tanked his season’s numbers. Loaisiga allowed 6 runs in 1.1 innings against the Twins on September 11, and allowed only 8 earned runs in 23.1 innings the rest of the year.

He’s shown improvement in every year since, but it seems that the move to the bullpen full-time has been a huge difference-maker. Without having to worry about stretching himself across 4 or 5 innings, Loaisiga is free to let it fly in a shorter outing. This can give his stuff more life, as well as working as a confidence booster.

Naturally, however, there is a lot more that has gone into his success.

Jonathan Loaisiga: Switching Pitches

One of the most notable progressions through Loaisiga’s career has been the use of his fastball. He has thrown the pitch less and less each year since his debut. In 2018, he threw the pitch 55.8% of the time. This season, he’s thrown the fastball only 14.3% of the time. His 4-seamer is now tied with his curveball as the two pitches he throws the least.

Instead, Loaisiga has replaced the typical 4-seamer with a sinker. He introduced the pitch in 2019, and its use has skyrocketed since then. Take a look at his usage chart, from Baseball Savant:

From 2018 to 2020, batters hit .299 in at-bats ending with the 4-seam. This season, hitters are just 4/21 (.190 average) in at-bats ending with Loaisiga’s sinker.

One factor to consider here also is that Loaisiga is simply mixing his pitches much more often. Going back to 2018, the righthander threw only three different pitch types all year, and relied on that fastball nearly 56% of the time. With the addition of the sinker, and increased confidence in his curve/change combo, no one pitch has been thrown more than 45% of the time this season.

Another interesting note is Loaisiga’s curveball. He’s throwing the pitch much less than in past years, but he’s also throwing it in different spots.

Take this, for example: In 2019, 72.5% of his curveballs were thrown against right-handed batters. In 2020, that dropped to 50%, and this year it’s 55.6%. Because his sinker breaks away from left-handed batters, it’s made his curveball (which breaks down and in to southpaws) more effective in those situations.

Changing up the Changeup

He’s also relied more on his changeup than in the past, as you can see on the above usage chart. In 2018 and 2019, the changeup was definitively his third pitch, with his primary offspeed offering being the curveball (I know, a curveball is a breaking ball, not offspeed). In 2018, the changeup represented 13.1% of Loaisiga’s pitches. So far this season, he’s thrown the pitch 27% of the time, with the curve now coming on only 14.3% of his pitches (31.1% in 2018). The two pitches have essentially traded places in Loaisiga’s repertoire (Again from Baseball Savant).

That’s been utilized to great effect, as well. Batters are hitting just .133 against the changeup, and their expected average is actually even lower, at .122. 7 of Loaisiga’s 13 strikeouts have also come via the changeup. It’s easily been his best pitch this season.

Jonathan Loaisiga: The Trust Factor

Loaisiga threw a scoreless 7th inning in the Yankees’ win on April 22. There’s one at-bat I wanted to highlight that really shows how much he’s grown to trust his changeup.

https://twitter.com/dylmcglynn/status/1386689844919812102?s=21

On a 2-2 pitch, Loaisiga goes to the change and misses up and away. He comes back to it again and leaves it elevated, but Rosario rolls over the top. In past seasons, Loaisiga might go to something else now. He’s thrown consecutive changeups, and the count is full. Instead, he trusts the pitch, and on the third try, buries a great one to get Rosario swinging to end the inning.

“The Trust Factor” doesn’t just refer to Loaisiga trusting his pitches, either. Two days later, the Yanks went right back to him, this time looking for a 4-out save.

It shows a lot of trust in the 26-year-old, giving him an opportunity to close while Aroldis Chapman was getting a day of rest. It also says a lot considering this game was Cole vs Bieber, and Loaisiga entered with a 2-1 lead. The Yankees know they can’t afford to waste Cole’s starts, so the decision to give Loaisiga the rest of the game really speaks to how much they trust him right now.

Jonny on the Spot

So, basically, Loaisiga throws his changeup more, his curveball less, and replaced his fastball with a sinker. The move to the bullpen has also allowed him to throw freely, without the pressure of necessarily staying as efficient with his pitches, or worrying about battling deep into games.

He has looked dominant on the mound this season, and is a key cog in the Bombers’ bullpen. As the team waits for Zack Britton to return, they will need to continue to rely on pitchers like Loaisiga in high-leverage situations. But if the start to this season is any indication, that won’t be much of an issue.