Tiki Barber
Giants running back Tiki Barber was 31 years old when he retired in 2006, not especially young for a player at his position, but he was playing the best football of his career at the time. His final three seasons featured his three highest rushing yard totals, and he rushed for over 200 yards in a game four times after turning 30. Barber achieved a successful broadcasting career after leaving the NFL, but it has to hurt that the Giants won a Super Bowl just one year after his retirement, something they never did when he was a member of the team.