Houston, TX (SportsNetwork.com) - The Oakland Athletics placed pitcher Drew Pomeranz on the 15-day disabled list Wednesday with a sprained left AC joint.

Pomeranz left in the fifth inning of Monday's 2-1 win at Houston with left shoulder tightness. He is 2-3 with a 4.40 ERA in eight starts this season.

The A's recalled right-hander Arnold Leon from Triple-A Nashville to fill the roster spot. Leon made his major league debut against the Angels on April 22, tossing one inning of relief. He was 0-2 with a 4.26 ERA in five starts for the Sounds.