Right-handed pitcher Juan Valera, Boston's No. 4 prospect, had Tommy John surgery on Wednesday. The procedure was performed by Dr. Jeffrey Dugas in Alabama.
Red Sox senior director of player development Brian Abraham confirmed the news to MLB.com's Ian Browne. Valera, 19, had been sidelined earlier this season after leaving an April 16 start against Bowling Green with elbow inflammation. He had posted a 1.93 ERA in three starts for High-A Greenville, striking out 17 batters in 9 1/3 innings with strong swing-and-miss stuff.