The play occurred in the fourth quarter of Pittsburgh's 23-14 victory, and McGahee was carted from the field on a stretcher.
"It is expected that Willis will have a complete recovery from the head and neck injuries he suffered last night," Ravens spokesman Kevin Byrne said Monday.
Although McGahee had significant neck pain, he had movement in his arms and legs after the hit. He was taken to UPMC Presbyterian Hospital and held overnight for observation. He was released early Monday morning and back home by early afternoon.
McGahee had just caught a pass and taken two steps before being met by Clark, who drove his helmet into McGahee's facemask. McGahee's head snapped back, and he lost the ball as he dropped to the ground.
Clark also collapsed, though it was immediately apparent that his injury wasn't serious.
Players from both teams gathered around McGahee, who lay motionless before being taken away.
Starting at tailback in place of the banged up Le'Ron McClain, McGahee ran for 60 yards and two touchdowns.
Copyright 2009 by The Associated Press