Cincinnati also waived receiver Armon Binns on Saturday. Binns played in eight games, starting two, and had 18 catches for 210 yards and a touchdown.
Cook hurt his right ankle during the final preseason game and needed surgery. Under a new rule in the NFL this season, teams can designate one player to return from the injury list. Cook resumed practicing last week and showed no lingering problems with the ankle. He started 50 consecutive games before the injury.
The Bengals (7-5) need a win against the Cowboys (6-6) to stay in the playoff chase.