The Bengals have signed 28-year old CB Keiwan Ratliff to replace Pat Sims on the active roster for the playoffs.  He played in 8 games for the Steelers this season making 9 tackles.  He has now played in 73 games (12 starts) in his NFL career and he has made 145 tackles, defensed 11 passes, forced 2 fumbles and he has 5 interceptions including one that he returned for a TD.  The addition of Ratliff should help them out on special teams.