Red Sox pitching prospect Yordanny Monegro will undergo Tommy John surgery after tearing the ulnar collateral ligament (UCL) in his throwing elbow, Double-A Portland manager Chad Epperson told Beyond the Monster’s Josh Ball on Wednesday.
Monegro has been on Portland’s 7-day injured list since June 14. In his start against Somerset the night prior, the 22-year-old right-hander left the mound with a trainer in the second inning after giving up a one-out RBI double to Cole Gabrielson. He appeared to be quite emotional as he made his way towards the visitors’ dugout.
As noted by Ball, Monegro was initially diagnosed with right elbow discomfort/inflammation (the same reason he was scratched from a start earlier this month) upon being placed on the injured list this past Saturday. Further imaging and testing (i.e., an MRI) revealed a torn UCL, leading to Wednesday’s announcement from Epperson that surgery was now necessary.
“This young man, and the work he was putting in, I think he finally figured that out,” Epperson said of Monegro. “The weight room, the nutrition, everything that he was going and buying into, he finally figured out that part of it, and to have this go and happen to him really sucks because you were starting to see results.”
In nine outings (eight starts) for Portland this season, Monegro posted a 2.67 ERA and 2.34 FIP with 49 strikeouts to eight walks over 33 2/3 innings in which opposing hitters batted .250 against him. Among 72 Eastern League pitchers who had thrown at least 30 innings in 2025 entering play Wednesday, Monegro ranked first in xFIP (1.73), second in groundball rate (57 percent), third in strikeouts per nine innings (13.10) and strikeout rate (35.8 percent), seventh in swinging-strike rate (15 percent), eighth in FIP, 16th in walks per nine innings (2.14) and walk rate (5.8 percent), 19th in ERA, and 33rd in WHIP (1.19), per FanGraphs.
Originally signed for $35,000 as an international free agent coming out of the Dominican Republic in February 2020, Monegro is currently regarded by Baseball America as Boston’s No. 17 prospect, ranking ninth among pitchers in the organization. The 6-foot-4, 180-pound hurler was getting his first taste of the upper-minors this year after spending most of last season at High-A Greenville. He was topping out at 96 mph with his mid-90s four-seam fastball while also mixing in a low-90s sinker, an upper-80s slider, an upper-70s curveball, and an upper-80s changeup.
If Monegr0 does indeed undergo Tommy John surgery in the coming days or weeks, he would be looking at a lengthy rehab process that would keep him sidelined for the remainder of the 2025 season and most, if not all, of 2026 as well. That depends on the extent of the damage to the UCL. However, in contrast to full-blown Tommy John surgery, an internal brace procedure typically offers a quicker recovery timeline but still comes with a sizable layoff.
That difference in downtime is relevant in the case of Monegro, who turns 23 in October and can once again become eligible for the Rule 5 Draft this winter if he is not added to Boston’s 40-man roster by the protection deadline in November. In a similar situation last year, the Red Sox elected to leave fellow righty Angel Bastardo (who was recovering from June 2024 Tommy John surgery) off their 40-man roster and subsequently lost him to the Blue Jays in December’s Rule 5 Draft. Bastardo has spent the entirety of the 2025 season to this point on Toronto’s 60-day injured list.
(Picture of Yordanny Monegro: Kelly O’Connor/sittingstill.smugmug.com)