Forsett, the NFL's 10th-leading rusher, was slammed to the ground by Rams defensive tackle Aaron Donald with 4:50 left in the first quarter. He was helped off the field with his right arm in an air cast.
Forsett had a productive start Sunday, gaining 31 yards on his first three carries.
Forsett's injury wasn't even the biggest of the day for a wounded Ravens roster as quarterbackJoe Flaccotore the ACL and MCL in his left knee on the final drive of the game. Baltimore (3-7) had already lost leading receiverSteve Smith Sr.to a season-ending Achilles injury three weeks ago.