PITTSBURGH — The San Diego Chargers elevated safety Tra Battle from the practice squad to the active roster today due to injuries.

To make room on the 53-man roster, rookie tackle Corey Clark was waived.

The Chargers needed to add a defensive back because cornerback Cletis Gordon is out with a knee injury and safety Steve Gregory is listed as questionable with a neck injury.

General manager A.J. Smith didn't return a phone call seeking comment.

The Chargers (4-5) play the Steelers (6-3) on Sunday. San Diego is 0-12 in regular-season games in Pittsburgh.