Tampa Bay Rays right-hander Tyler Glasnow has a partially torn ulnar collateral ligament and a flexor tendon strain, the team said Tuesday after he underwent an MRI.
The Rays said a timeline for Glasnow's possible return would be determined after he undergoes further medical examination.
Glasnow will be placed on the 10-day injured list and outfielder Mike Brosseau will be recalled from Triple-A Durham.
Glasnow left Monday night's game against the Chicago White Sox after four innings with right elbow inflammation.
He allowed two runs on three hits and exited with Tampa Bay leading 3-2 in a matchup of teams that entered with the two best records in the majors.