Cook (undisclosed) has been ruled out for Thursday's preseason game against Detroit, Ben Baby of ESPN.com reports.
Cook has been working through an unspecified injury since Sunday. The injury will prevent him from playing in Thursday's preseason opener, and the Bengals' next exhibition game takes place Saturday, Aug. 22 against the Bears. Kyle Dugger and PJ Jules will both see more reps at safety alongside Jordan Battle while Cook is sidelined.