Houston ? Astros right-hander Brandon Backe underwent ligament replacement surgery on his pitching elbow Thursday, and his recovery is expected to last a year to 18 months.

Backe twice sprained the ulnar collateral ligament this season. He decided to have season-ending surgery, which was performed by Dr. James Andrews in Birmingham, Ala.

The 28-year-old pitcher went on the disabled list April 14 and returned July 22. He made six starts before re-injuring the elbow. He went back on the DL on Aug. 19.