PITTSBURGH — The Pittsburgh Steelers will be without injured Pro Bowl running back Willie Parker and nose tackle Casey Hampton for Monday night's home game against Baltimore.

Parker, who had 243 yards in the Steelers' first two games before being held to 20 during a 15-6 loss at Philadelphia on Sunday, has a sprained left knee that occurred late in that game.

Steelers coach Mike Tomlin did not say Tuesday if Parker might miss more than one game.

With Parker out, first-round draft pick Rashard Mendenhall will make his first NFL start. Mendenhall, from Illinois, has 28 yards in 10 carries during limited playing time — partly because he fumbled three times in the final two exhibition games.

Hampton, a Pro Bowl defensive lineman the last four seasons and the key to the Steelers' run defense, has a strained groin. He will be replaced by Chris Hoke, who made 10 starts in 2004 after Hampton injured a knee.

Defensive end Brett Keisel, who sat out the Eagles game with a calf injury, is also out. He may be sidelined for a month or more.

Ben Roethlisberger, sacked eight times by the Eagles, injured his right hand late in the game but is not expected to be limited in practice, Tomlin said.

Tomlin said no personnel moves will be made along the offensive line, despite the repeated breakdowns in protection that had Roethlisberger constantly ducking defenders. The Steelers (2-1) were held to 160 yards, with 33 yards rushing on 19 carries.

Parker was leading the NFL in rushing with 1,316 yards when he broke his right leg on a carry early in the Steelers' Dec. 20 game at St. Louis last season. Without Parker, the Steelers ran for only 92 yards combined in their final two games, a 27-21 regular-season loss at Baltimore and a 31-29 wild-card playoff loss at home to Jacksonville.

That inability to run the ball effectively without Parker led the Steelers to draft Mendenhall.