Indianapolis signed running back Najeh Davenport to shore up a suddenly injury-depleted backfield.
Coach Tony Dungy had said Monday the Colts would add a running back if there was concern starter Joseph Addai could not play Sunday against Detroit because of a right shoulder injury. No. 3 back Chad Simpson, who also returns kickoffs, sprained his ankle in last week's 35-3 victory over the Bengals and is unlikely to play against the Lions.
That would have left Indy (9-4) with Dominic Rhodes as the only running back on the active roster.
Davenport is in his seventh NFL season and was originally drafted by Green Bay. He played with Pittsburgh in 2006 and 2007 and has had two stints with the Steelers this season. He was released Dec. 1.
"He could be playing right away," Dungy said. "He has had some familiarity with our system because he worked with [offensive coordinator] Bruce Arians in Pittsburgh."
Arians was a quarterbacks coach with the Colts earlier this decade.
To make room for Davenport, who has rushed for 1,793 yards and 13 touchdowns, the Colts waived tight end Jamie Petrowski.
But the Colts also could be getting one key player, center Jeff Saturday, back. Saturday has missed two straight games since straining his left calf. Dungy said he could have played last week against the Bengals, but they decided to hold him out.
"I'm doing good, I practiced some last week, so we'll see how it turns out," Saturday said. "I felt really close last week, and I hope everything has progressed."
Middle linebacker Gary Brackett, the Colts' defensive captain, was back in the locker room in a walking boot. He sat out last week with a cracked bone in his lower right leg and is expected to miss a second straight game this week.