Joe Flacco's left knee "caved in" when he was hit by DeAndre Levy's helmet just below the knee.
Flacco got back up gingerly, but stayed in the game.
"It feels fine," Flacco said. "It feels strong."
The potential for injury looked so serious that the Ravens had Tyrod Taylor begin to warm up.
Flacco got the knee taped up and went back in the game on the next possession.
Flacco had a slight limp after the game.