The Ravens are thin at cornerback and getting thinner.
Cornerback Asa Jackson left Thursday night's game with a concussion, suffered when he was in on a third-down run stop and pile up during the second quarter.
Jackson immediately went to the locker room to be evaluated, and it was later announced that he had indeed suffered the head injury and would not return.
"I don't think it's too major," Head Coach John Harbaugh said after the game. "But again, you never know with those things."
That leaves Baltimore with just two healthy cornerbacks against the Steelers: Jimmy Smith and Chykie Brown.
The Ravens are using free safety Matt Elam as the nickel cornerback with Smith and Brown outside. They have brought in safety Jeromy Miles to take Elam's place in such situations.
The Ravens are already without cornerback Lardarius Webb (back), who has been out since the second day of training camp. He is inactive for the second straight regular-season game.
Harbaugh also said two other players suffered ankle and knee injuries in Thursday night's game, but did not specify who they were.
"They don't look too bad," Harbaugh said.