Red Sox prospect Yordanny Monegro’s breakout season at Double A Portland has come to an early end, as the righthander has been diagnosed with a torn ulnar collateral ligament and will require Tommy John surgery, according to a major league source.
Monegro, 22, was 2-1 with a 2.67 ERA and a 36 percent strikeout rate (third highest in the minors among pitchers with at least 30 innings) this season. With a four-pitch arsenal (cutter, curveball, mid-90s fastball, splitter), he’d been getting a lot of swings and misses.
“This is the best version of Monegro we have seen from his work and preparation to the execution of his plan,” Red Sox director of pitching Justin Willard texted in late May. “It’s always been fun to watch him compete, but now he is doing the other things to take the next step.”
But Monegro, after a six-inning outing on June 1, didn’t make another start until June 13. He lasted just 1⅓ innings in that outing, and required an MRI this week because of elbow discomfort. The discomfort offered the worst-case scenario, with Monegro to miss the rest of 2025 and most or all of 2026.
Alex Speier can be reached at alex.speier@globe.com. Follow him @alexspeier.