The Cincinnati Bengals placed linebacker Thomas Howard on injured reserve Friday.
Howard tore his ACL during practice on Thursday. He had three tackles and a sack against the Ravens on Monday.
The 29-year-old Howard had 99 tackles and one sack in 16 games for the Bengals in 2011.
Over 93 career games with Oakland and Cincinnati, Howard has 492 tackles, six sacks and seven interceptions.
The Bengals brought back linebacker Roddrick Muckelroy to fill the roster spot. Muckelroy, who was part of the team's final cuts, played in 14 games for Cincinnati during the 2010 season.