Colorado coach Deion Sanders may be losing a tailback but gaining a future dentist. Charlie Offerdahl has announced his retirement from football due to a history of concussions.

Last season, Offerdahl played in 13 games, rushing for 126 yards and one TD. He wore an “L” on his jersey to signify “leader.” “Charlie never had a bad day," Sanders said.

Colorado’s Charlie Offerdahl, right, celebrates his touchdown against Utah on Nov. 16 at Folsom Field. (Cliff Grassmick/Staff Photographer) Colorado running back Charlie Offerdahl is retiring ...

Charlie Offerdahl stood in front of his teammates and coaches on the first day of fall camp Tuesday and announced he’s retiring from football due to a history of concussions.

FILE - Colorado running back Charlie Offerdahl (44) runs the ball behind lineman Van Wells (55), who looks to block Arizona's Christian Young during the first half of an NCAA college football game ...

Charlie Offerdahl stood in front of his teammates and coaches on the first day of fall camp Tuesday and announced he's retiring from football due to a history of concussions.