Brandon Weeden replaced an injured Jason Campbell at quarterback for a few plays late in the first quarter for the Browns.
Campbell was hurt after Ravens nose tackle Haloti Ngata fell on top of Campbell while he was scrambling.
Ngata was flagged for unnecessary roughness on the play, but it was a controversial flag.
Ngata lost his feet as he was chasing Campbell, making it difficult for Ngata to avoid falling on top of Campbell.
Campbell rose slowly to his feet after about 30 seconds and walked slowly to the sideline.
The Browns announced Cambell had an injury to his ribs, and that his return was probable.
Campbell was playing well, having already led the Browns on a touchdown drive.
He reentered the game on the next series, drawing cheers from the crowd.