BEREA, Ohio-- Browns starting linebacker D'Qwell Jackson is one of several notable players missing from practice.
Jackson wasn't on the field Wednesday after sustaining a concussion in Sunday's loss to the New York Giants.
Browns coach Pat Shurmur said Jackson was at the team's facility and attended meetings.
He is the only player in the NFL with at least two sacks and two interceptions. If Jackson can't play Sunday against Cincinnati, rookies L.J. Fort or Craig Robertson could get significant playing time.
The winless Browns (0-5) were also missing wide receivers Mohamed Massaquoi (hamstring), Travis Benjamin (hamstring) and Jordan Norwood (foot), who had nine catches against the Giants.
Defensive tackle Ahtyba Rubin (lower leg) and cornerback Dimitri Patterson (sprained ankle) are also out.
Tight end Alex Smith returned after missing three games with a concussion.