The Athletics voided Holman's optional assignment to Triple-A Las Vegas on Thursday and placed him on the 15-day injured list (retroactive to Monday) with rotator cuff tendinitis in his right shoulder.
The A's originally optioned Holman to Triple-A on Monday after he had posted a 5.09 ERA in 23 innings with the major-league club. However, the team uncovered a shoulder injury Thursday and will keep him around to rehab with the big-league squad. He'll be eligible to return from the IL beginning July 1, though he may still be sent down to the minors whenever he's fully healthy.