Dubin has been placed on the 7-day injured list at Triple-A Sugar Land with a right elbow strain, Brian McTaggart of MLB.com reports.
The 27-year-old righty could have been an option for spot starts in the big-league rotation amid recent injuries to Luis Garcia and Jose Urquidy if he'd been pitching well and was healthy. However, Dubin had a 6.27 ERA and 1.45 WHIP in 18.2 innings prior to the injury. He should be considered out indefinitely.