Holt will replace rookie Zackary Bowman, who suffered a season-ending biceps injury Sunday against Minnesota. He is quite familiar with the NFC North, having spent his first four seasons with Detroit before moving to Arizona last season. Holt went to training camp with Carolina this summer but was released after the preseason.
The signing indicates the Bears aren't totally sure of their health situation. Cornerbacks Charles Tillman (shoulder), Nate Vasher (wrist) and Danieal Manning (hamstring) all missed Sunday's game and probably won't practice during the bye week.