The Steelers' main injury worry following their 15-6 loss Sunday in Philadelphia was the punishment quarterback Ben Roethlisberger took while being sacked eight times. He played with a slight shoulder separation, and a right hand injury sidelined him late in the fourth quarter.

When Tomlin revealed his updated injury list Tuesday, Roethlisberger wasn't on it, but Parker unexpectedly was — the Pro Bowl runner has a sprained left knee that will keep him out of Monday night's home game against Baltimore (2-0).

Both the offense and defense will be missing key players. Four-time Pro Bowl defensive lineman Casey Hampton (groin sprain) also won't play and defensive end Brett Keisel (calf) will miss a second successive game. Chris Hoke, who made 10 starts in 2004, replaces Hampton.

Tomlin wouldn't discuss the specifics of Parker's injury or whether he might also miss the Oct. 5 game at Jacksonville, although that seems likely.

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

Is he ready after failing to get any carries in the past two games?

"Ready or not," Tomlin said. "No, Rashard is ready. He's a talented guy. He's been practicing well and he gets his opportunity. You see a lot of his peers around the league and they've been getting opportunities, partly because they don't have Willie Parker playing in front of them."