NEW YORK — The Yankees have promoted one of their most prolific strikeout arms to Triple-A, putting Xavier Rivas one step from the majors after a breakout run at Double-A Somerset.
Rivas was assigned to Scranton/Wilkes-Barre this week after overpowering Eastern League hitters despite possessing anything but an overpowering fastball.
The 24-year-old left-hander went 6-4 with a 3.64 ERA across 19 appearances, including 15 starts, for Somerset. He struck out 114 batters in 81 1/3 innings while allowing only 51 hits and holding opponents to a .176 batting average.
The promotion gives the Yankees another upper-level pitching option to watch for 2027. MLB Pipeline currently ranks Rivas No. 23 in New York’s system and lists his estimated major league arrival as next season.
What makes his rise unusual is how those strikeouts are being generated.
Rivas does not possess the high-octane fastball associated with many of the Yankees’ young pitchers. His heater generally sits between 90 and 92 mph. Instead, a low-80s changeup with splitter action and a tight slider have become his primary swing-and-miss weapons. MLB Pipeline says the changeup generated a 57% whiff rate during his professional debut.
Rivas forced promotion with dominant Double-A run
The Yankees did not move Rivas because of one hot start.
He had been building toward Triple-A for weeks.
Rivas posted a 1.45 ERA over his final 10 appearances with Somerset and allowed no more than two earned runs in any outing during that stretch.
His most dominant performance came July 12, when he delivered six hitless innings and struck out 10.
The performance was among the notable developments in the Yankees farm system.
The strikeout numbers became increasingly difficult to overlook.
Prospect Savant data cited in the supplied reporting placed Rivas’ 34.3% strikeout rate in the 90th percentile. His 35.7% whiff rate ranked in the 86th percentile, while his swinging-strike rate ranked in the 82nd percentile.
That production came after Rivas moved rapidly through the Yankees system.
New York selected the 6-foot-4, 235-pound left-hander in the 16th round of the 2024 MLB draft. Rivas had missed his final season at Ole Miss after undergoing Tommy John surgery.
He began his professional career in 2025 and moved through Rookie ball, Single-A Tampa and High-A Hudson Valley before opening this season with Somerset.
Across his first two professional seasons, Rivas has recorded 227 strikeouts in 166 2/3 innings with a 3.51 ERA, according to the supplied minor league statistics.
Yankees have an unusual strikeout arm
Rivas’ arsenal is what separates him from the typical strikeout-heavy pitching prospect.
MLB Pipeline grades his fastball at 40 on the 20-80 scouting scale. His changeup receives a 60, while the slider carries a 55 grade.
That creates an unusual formula.
Rivas uses a below-average fastball to establish the strike zone before asking hitters to distinguish between two low-80s secondary pitches capable of disappearing beneath barrels.
His changeup has particularly unusual characteristics.
“Rivas doesn’t fool hitters with a riding fastball that sits at 90 mph and maxes out at 92, but he utilizes it well enough to set up a pair of baffling secondary pitches,” his MLB Pipeline scouting report says.
The Yankees prospect kills spin on the changeup, creating splitter-like movement. His slider gives him another pitch capable of finishing hitters when they protect against the changeup.
There are questions.
Rivas walked 41 hitters in 81 1/3 innings at Somerset, and MLB Pipeline has identified his command as a reason he could ultimately fit better in relief than in a major league rotation.
But hitters have struggled to punish those mistakes.
His .176 opponents’ batting average at Double-A illustrates how difficult it has been to square him up even when the command has wavered.
Triple-A gives Yankees their next answer
Rivas’ first Triple-A appearance Thursday provided an immediate reminder that the final step will not necessarily be smooth.
The left-hander allowed six earned runs on two hits and four walks while recording two outs against Lehigh Valley. He struck out one and took the loss in Scranton/Wilkes-Barre’s 11-3 defeat.
One outing does not change why the Yankees promoted him.
It does identify the next challenge.
Triple-A hitters should be less willing to chase Rivas’ secondary pitches outside the strike zone. That puts greater pressure on him to improve his fastball command and get into counts where the changeup and slider can take over.
The Yankees also have time to determine whether his future lies in a rotation or bullpen.
MLB Pipeline already views Rivas as more likely to become a deceptive left-handed reliever than a long-term starter.
A relief conversion could allow him to lean even more heavily on the two pitches responsible for his strikeout surge and potentially add velocity in shorter appearances.
For now, New York has not made that move.
The Yankees have instead given Rivas the opportunity to keep starting and prove his unusual formula can survive against Triple-A hitters.
Two years after taking him in the 16th round following Tommy John surgery, the Yankees have a 24-year-old left-hander at the highest level of the minors with 114 Double-A strikeouts behind him and a potential 2027 opening in front of him.
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