The Bengals placed linebacker Thomas Howard on the reserve/injured list Friday, after suffering a season-ending knee injury in practice this week.
Howard, a seven-year veteran from UTEP, was Cincinnati's tackling leader last season with 120 stops, and started in the Bengals' Week 1 loss to the Ravens on Monday night. He had four tackles, including a sack, and a pass defensed in the 44-13 defeat.
To take his place on the roster, Cincinnati signed linebacker Roddrick Muckelroy. A third-year player from Texas, Muckelroy started three preseason games for the Bengals this summer, posting 17 tackles, including a sack. He was a fourth-round draft choice in 2010 by Cincinnati.
The Bengals (0-1) take on the Browns (0-1) on Sunday.