Steelers' starting left tackle Max Starks' knee injury is serious enough that he will not play again this season, coach Mike Tomlin said.
Starks has a meniscus injury that will require surgery.
Also, the Steelers will place special teams captain Clint Kriewaldt on injured reserve with a continuing neck injury.
The Steelers will sign two players to replace them on their 53-man roster.
Starks is the second left tackle the Steelers have lost. Regular starter Marvel Smith cannot play after having back surgery last week, although he has not yet been placed on injured reserve.
Starks' left knee injury means that Trai Essex, who played the final three quarters in Baltimore, likely will start at left tackle Saturday night in the first playoff game at Heinz Field in three years.