HOUSTON -- The Houston Astros placed right-hander Roy Oswalt on the 15-day disabled list prior to their game with the Chicago Cubs on Tuesday and purchased the contract of left-handed pitcher Phillip Barzilla from Triple-A Round Rock.
To make room for Barzilla on the 40-man roster, the Astros transferred right-hander Brandon Backe from the 15-day to the 60-day disabled list. Barzilla, a former Rice University pitcher, is in uniform for Tuesday's game.
Oswalt, whose disabled stint is retroactive to May 30, is suffering from a strain in his middle back on the left side, an injury that kept him from starting Sunday against the Reds.
Oswalt will be eligible to come off the DL on June 14.
Alyson Footer is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.