21. Robert Smith:
Smith was highly-touted prospect coming out of Ohio State when the Minnesota Vikings drafted him in the first round of the 1993 NFL draft. However, it would take him quite a few seasons before he finally found his groove in the NFL. In 1997, he had a breakout season with 1,266 yards rushing, But the best was yet to come. He followed that up with his finest season when he led the league in rushing with 1,521 yards in 2000. Smith was the rare running back who got better with age.
Despite that fact, however, he would shock the football world by retiring from the sport after what was by far his best season. Smith went on to pursue a career as a doctor before any serious injuries added up in football. He’s recently appeared as an analyst on ESPN but has otherwise stayed out of the sporting spotlight.