"There figures to be running room Sunday when the Indianapolis Colts take on Detroit's No. 31 rushing defense at Lucas Oil Stadium, but it was unclear Friday who would be doing the running.

Starter Joseph Addai (shoulder) hasn't practiced all week. No. 3 running back Chad Simpson (ankle) practiced for the first time Friday. Both are listed as questionable, and Najeh Davenport, a free agent signed Tuesday, is cramming to learn the complexities of the Colts' no-huddle offense.

Dominic Rhodes would seem destined to get the bulk of the carries.

"My sense is we'll probably hold (Addai) out if there's any question at all," Colts coach Tony Dungy said.

If Simpson is able to play, he would back up Rhodes but not return kickoffs. Davenport would handle kicks, and if he has to play running back, the Colts would adjust.

"When he's in there, we'll probably have to huddle a little bit and make sure we get him as much information as we can," Dungy said.

Dungy expects left tackle Tony Ugoh (knee) to be ready, but he was less certain about safety Bob Sanders, who practiced for the first time Friday."