He has only been the starter for 3 1/2 years. The first 5 years in the league he averaged 51 carries a season. I could see if he has been a featured back for the past 8 years but he has not. There is still plenty of tread on that tire. Add to the fact that at Kansas he was only the starter for his senior year. Unlike most backs at his age he has probably had half the carries that a feature back from college to the age of 30 would have.