Houston, TX (Best E Casino) - The Houston Astros placed pitcher Roy Oswalt on the 15-day disabled list Saturday. The move is retroactive to July 12.

The 30-year-old hurler underwent an MRI earlier in the day, which confirmed a strained left hip abductor injury as well as a lingering, minor herniated disc.

Oswalt, the ace right-hander, has struggled to a 7-8 record with a 4.56 earned-run average this season over 17 starts.

To take his place on the roster, the Astros recalled pitcher Runelvys Hernandez from Triple-A Round Rock. Hernandez was 0-3 with a 10.29 ERA in three starts with Houston this season, but is expected to make a start for the club on Monday against the Pittsburgh Pirates.