Steelers quarterback Byron Leftwich, expected to start during Ben Roethlisberger's suspension, has injured his left knee during the first half of an exhibition game against Carolina.
Leftwich completed an 18-yard pass to rookie Emmanuel Sanders before being knocked off his feet as running back Mewelde Moore attempted to block safety Marcus Hudson. The play occurred with 10:25 left in the second quarter Thursday night.
Leftwich was examined by team doctors on a stretcher behind the Steelers' bench, then limped into a nearby tunnel that leads to the locker room. Team officials said he would not return to the game.