The Ascent of Jonathan Loáisiga By the Numbers


Perhaps no entry on the Yankees’ unimaginably lengthy injury list is as disheartening as Luis Severino’s Grade 2 lat strain. New York’s homegrown ace and linchpin of its championship aspirations will be sidelined until mid-June at the earliest – and in the meantime, the team will have to construct a rotation capable of surviving the increasingly daunting AL East gauntlet. CC Sabathia’s return from injury and suspension will help, but the Yankees will be forced to rely on promising but unproven arms like Domingo Germán, Luis Cessa, and Jonathan Loáisiga for quality innings until Severino can return.

The 24-year-old Loáisiga ranked as the #2 prospect in the Yankees organization by MLB Pipeline and FanGraphs, is a compelling story in more ways than one. Just the 15th player and 11th pitcher from Nicaragua to appear in the major leagues, Loáisiga was picked up off the scrap heap at a showcase in Venezuela in 2016 after washing out of the Giants’ system due to injuries and endured Tommy John surgery before breaking out at Double-A Trenton last year. The right-hander’s gaudy numbers for the Thunder (28.4 K%, 2.80 xFIP) earned him the express lane to his Yankees debut, as he appeared in the bigs for the first time on June 15 in place of the injured Masahiro Tanaka without having thrown a single pitch in Triple-A.

Loáisiga’s meandering path to The Show resulted in four starts for a total of 18 innings last season and a few relief appearances once rosters expanded in September. With Severino and Sabathia unavailable to begin 2019, he made two more starts this year before being optioned to Scranton. All this is to say; a massive small-sample-size disclaimer has to be applied to any analysis of his infant career. It’s difficult to make any broad pronouncements from what amounts to a classic cup of coffee in the majors, but there are still some trends worth examining.

There are obvious reasons for Loáisiga’s placement near the peak of prospect charts everywhere. His stuff is electric – his four-seamer sits at 95-96 and tops out at 98, his breaking ball carried a chase rate of 41 percent, and he flashed a devastating fading changeup that he threw almost exclusively to lefties, but that also showed signs of developing into a put-away offering. Loáisiga’s minor league stats showcase promising command and control as well, as he posted a minuscule 1.3 BB% with Single-A Tampa and 4.3 with Trenton. While he didn’t pitch deep into games during his four-start cameo, Loáisiga waltzed into the majors and missed bats at an impressive clip. His adjustment from Double-A hitters to big league veterans was remarkably swift, and his overall body of work was impressive.

Still, in his six career starts, Loáisiga only recorded an out past the fifth inning in one and failed to pitch out of the fourth in four. While he did not have issues maintaining his velocity the second time through the order, he became a markedly less effective pitcher. Conventional stats tell part of the story here – Loáisiga’s ERA ballooned from 0.93 to 6.40 and his wOBA against from .231 to .372 when facing opposing batters for the second time last year. Exit velocity and batted-ball metrics confirm these numbers, as Loáisiga’s line-drive rate and hard-contact rate both jumped significantly the second time through. Pitch tracking data adds another dimension. Loáisiga’s breaking ball, a whiff-generating machine when hitters faced him the first time, faded when those hitters saw it again. An elite 30 percent whiff rate on the pitch was more than halved as the lineup turned over, per Brooks Baseball. Having seen Loáisiga’s offering once, hitters appeared to settle in and pick up the spin more easily.

Even more telling is the head-scratching numbers surrounding Loáisiga’s fastball. Its velocity, averaging 96.1 MPH, ranked in the 89th percentile and its spin rate in the 74th percentile last year, per Baseball Savant. Just four starters with qualifying innings totals in all of baseball averaged 96 or above on their four-seamers last season: Severino, Gerrit Cole, Mike Foltynewicz, and Jacob deGrom. That is good company. All four of those pitchers made All-Star teams.

These numbers make the next bit of information all the more mystifying. Those four All-Stars generated the following swinging-strike percentages with their four-seamers: 9.1, 13.8, 7.2, and 16.2, respectively. Foltynewicz’s number is by far the lowest of the four, but he is a less comparable case because he also mixes in a sinker and only features his four-seamer 40 percent of the time. Loáisiga’s four-seamer, which he threw at similar rates to Severino, Cole, and deGrom, generated a paltry 6.8 percent swinging strike rate. Elite velocity, above average spin, and just not missing bats. It’s a disappointing paradox, and Loáisiga will struggle if opposing hitters stay locked on his heater.

Now that Sabathia is back in the Bronx, Loáisiga will most likely slide into the Scranton rotation for a time, and his first career appearances at the Triple-A level will allow him the necessary space to develop his stuff. He is, of course, far from a finished product. Look for him to continue working on his promising changeup. If perfected, it will keep hitters off balance and may remedy his predictability. Provided he makes progress, Loáisiga may add even more enjoyable chapters to the story of his improbable rise.

All stats from Fangraphs unless noted.