In Week 12 of the 2012 NFL season, Green Bay Packers safety Sean Richardson injured his neck and required cervical spinal fusion surgery in January 2013.
Amazingly, Richardson was not only cleared to return to football in late October 2013 by a Packers medical staff that has proved to be reticent to do just that in the past—recently, safety Nick Collins' football career ended after no team, including the Packers, would clear him to play—but was a valuable player on that team.
Former Packers safety M.D. Jennings was struggling at the end of the 2013 season, and after his return from spinal fusion surgery, Richardson usurped more of Jennings' snaps until he eventually replaced Jennings outright.