Cleveland Indians hard-throwing reliever Emmanuel Clase could miss eight to 12 weeks of action because of a moderate strain of the teres major muscle in his upper back, the team announced Thursday.
An MRI performed Wednesday confirmed the diagnosis, and the team said he will be re-evaluated weekly.
The 21-year-old right-hander previously reported some pain in his arm, and he had yet to throw live batting-practice at the team facility in Goodyear, Ariz., or appear in a spring training game.
"You know what? We're actually kind of surprised that it was that length because he wasn't complaining about it very much at all," Indians manager Terry Francona said, per the team website. "Obviously he must be a pretty tough kid. Now, the rehab and the way he progresses goes completely on how he's feeling."
The Indians acquired Clase in December in the deal that sent two-time American League Cy Young Award winner Corey Kluber to the Texas Rangers.
Clase appeared in 21 games with the Rangers last season, and his average fastball velocity was 99.2 mph. He was 2-3 with a 2.31 ERA, striking out 21 in 23 1/3 innings.
His injury is the latest to strike Cleveland pitchers. Starter Mike Clevinger (partially torn meniscus), Carlos Carrasco (mild hip flexor strain) and Aaron Civale (groin) are sidelined at spring training.
--Field Level Media