Linebacker Jayson DiManche suffered a broken right forearm in Sunday's 14-13 win at Tampa Bay, and the Bengals placed him on season-ending Injured Reserve today.
An undrafted second-year player from Southern Illinois, DiManche has appeared in every game this season, mostly on special teams, where he played about 80 percent of the snaps.
DiManche had seven tackles on defense and three on special teams in addition to a forced fumble on special teams.
No corresponding move is expected until tomorrow.
DiManche is the sixth player to go on IR this season, joining right tackle Andre Smith, wide receiver Marvin Jones, linebacker Sean Porter, guard Trey Hopkins and cornerback LaVelle Westbrooks. Tight end Tyler Eifert is on Injured Reserve with the designation for return, but he has yet to practice since suffering an elbow injury in the season opener at Baltimore.