Detroit determined Ansah and running back Dwayne Washington would be inactive at Chicago after they didn't practice for a third straight day. Ansah also missed the previous game, a win over Cleveland. Washington is out with a hip injury.
Don Carey, a standout on special teams, and linebacker Jalen Reeves-Maybin are listed as questionable to play against the Bears because of ankle ailments.
Detroit (5-4) has not lost an NFC North game going into its matchup against the last-place Bears (3-6) on Sunday.