When Barry Sanders retired after the 1998 season, it was abrupt and somewhat controversial. Fans were upset he retired at the peak of his game, and just 1,457 yards short of breaking the NFL all-time rushing record. But Sanders didn't feel he could give his all to the game anymore, so he left.
Sanders' choice to leave was new territory when he did it, but now more players are making similar decisions. Just this week we've seen D'Brickashaw Ferguson (32) and A.J. Tarpley (23) retire. Earlier this offseason fans were heartbroken when Calvin Johnson decided to leave the game at 30 years old.