Two more players were signed and two more sent packing by the Steelers today as they try to improve their special teams play, particularly their kickoff coverage.

Linebacker Donovan Woods, signed from the practice squad last week, and veteran cornerback Keiwan Ratliff were released. Taking their places are two NFL veterans, cornerback Corey Ivy and linebacker Rocky Boiman.

Ivy, 32, has played for five NFL teams, most recently the Baltimore Ravens, whom the Steelers play Sunday night. He played for Baltimore the past three seasons. He was released by the Cleveland Browns after spending this summer in training camp with them.

Ratliff made the Steelers after signing with them as a free agent last spring. Woods last week replaced Arnold Harrison after he was released.

Coach Mike Tomlin said today he would move aggressively to change his team's ills, which include four kickoff returns for touchdowns against them in the past five games.

The Steelers also signed offensive lineman Jonathan Palmer to their practice squad and released running back Justin Vincent.

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