Polamalu returned to practice this week, but in a limited form. He did not practice with the defense, strictly working with the scout team. He has not played since spraining the medial collateral ligament in his left knee in the opener.
He set his target date for Sunday in Detroit, but the Steelers will wait until at least the Oct. 18 game against Cleveland in Heinz Field for his return.
Parker has turf toe and has not practiced this week. Combined with Rashard Mendenhall's performance last Sunday against San Diego, the Steelers see no reason to rush Parker back. Mendenhall rushed for 165 yards and two touchdowns in his breakout game against the Chargers.
Mendenhall, expected to make a second consecutive start for the first time in his two-year career, could even nail down the starter's job with a good performance in Detroit.
"His body of work isn't large enough yet to say I'm going to do that," offensive coordinator Bruce Arians said. "Now if he comes out and does it again this week? Yeah, then you have to re-evaluate the number of carries both guys get. But until he's a proven commodity ... Willie Parker is a proven commodity. And when Rashard is, yeah, then we'll re-evaluate who's getting what.
"I hope to get to that problem. I'd like to have two healthy running backs with those two at the same time."
- RB Isaac Redman, who was signed from the practice squad for last week's game, was released Monday and re-signed to the practice squad. If Willie Parker (turf toe) cannot go, there's a good chance Redman again would be signed Saturday to the 53-man roster for running back depth.
- G Chris Kemoeatu, who returned to practice on a limited basis Thursday, will start Sunday. Kemoeatu has a left ankle injury.
- CB Deshea Townsend continues to practice at strong safety, where he played some last week, alternating with starter Tyrone Carter, Troy Polamalu's replacement.
- CB Ike Taylor, who starts on the right side, has prepared all week to follow around Detroit WR Calvin Johnson on Sunday. However, if Johnson (thigh) does not play, Taylor will remain on the right side.
- RB Rashard Mendenhall has taken over the job as the Steelers' short-yardage back. That has been a problem for the team the past three years, but he scored from the 1- and 2-yard lines last week, so he has added that assignment to his duties.