Pittsburgh rookie Rashard Mendenhall fractured a shoulder in last night's 23-20 overtime win over the Baltimore Ravens, leaving the Steelers with one healthy running back.

Mendenhall will have surgery and be placed on injured reserve, ending his season, the National Football League team said on its Web site. Running back Willie Parker won't play in this weekend's game because of a knee injury, while Carey Davis is recovering from a sprained ankle.

With only Mewelde Moore healthy, the Steelers may try to sign two running backs before the Oct. 5 game against the Jaguars in Jacksonville, Florida.

Moore "is capable and has done it in his career," head coach Mike Tomlin said on the team's Web site. "Maybe not for 16 games, but there have been stretches, eight or 10 games, where he's capable of doing that and has done it in his career. We're going to weigh all our options."

Guard Kendall Simmons is also out for the rest of the season after tearing his right Achilles, the Steelers said.