Graham went down untouched Sunday after catching a pass from Josh Freeman, falling to the turf before being hit for a 2-yard loss.
He needed help leaving the field, struggling to put weight on his right leg. He was taken to the locker room for an examination and ruled out for the rest of the game.
Graham started for the injured LeGarrette Blount. The 31-year-old Graham was coming off his best game in three years, rushing for 109 yards in a win over the New Orleans Saints last week.
He had two carries for 13 yards against the Bears before being hurt.