Shaking up the bottom of their roster, the Steelers signed LB Rocky Boiman and CB Corey Ivy on Tuesday and cut CB Keiwan Ratliff and LB Donovan Woods.

Ivy, a nine-year veteran who last played with the Browns in training camp, and Boiman, an eighth-year pro who was last with Tennessee, have extensive special-teams experience, and both could immediately get playing time on the Steelers' kickoff-coverage unit, which has allowed four touchdowns this season.

Ratliff appeared in eight games this season for Pittsburgh. Woods lasted just a week on the Steelers' active roster; he was signed from the practice squad to replace Arnold Harrison last week.