Amukamara suffered a hamstring injury in a win at Detroit last Thursday and didn't practice this week. Kevin Toliver would likely start in place of Amukamara.
The Bears ruled out tight end Ben Braunecker (concussion), receiver Taylor Gabriel (concussion), offensive tackle Bobby Massie (ankle) and linebacker Danny Trevathan (elbow). All four also missed the win last Thursday.
Kickoff between the Bears (6-6) and Cowboys (6-6) comes at 7:20 p.m. Thursday from Soldier Field.