The Bears will likely turn to Kevin Toliver at cornerback in place of Amukamara. Toliver has made one start during his two-year NFL career.
Linebacker Danny Trevathan (elbow), offensive tackle Bobby Massie (ankle), tight end Ben Braunecker (concussion), receiver Taylor Gabriel (concussion), tight end Eric Saubert and offensive lineman Corey Levin are also inactive.
The Cowboys ruled out pass rusher Leighton Vander Esch on Wednesday.
Kickoff between the Bears (6-6) and Cowboys (6-6) comes at 7:20 p.m. from Soldier Field.