How about Robert Edwards?
Good career at Georgia. Got picked in the 1st by New England in '98. He ran for 1,115 yards as a rookie and then blew out his knee at a rookie flag football game in Hawaii. They even thought he may never walk again it was so bad.
Then he made a short comeback in '02 with the Dolphins. I know it was pretty awesome to see him on the field. His 1st game back he had 2 touchdowns.
I think he also got the Halas Award for the comeback.