15. John Stephens
Stephens was another running back who peaked far too early. By too early, we mean in his rookie season. He put up some excellent numbers as he demonstrated his athletic ability. The Offensive Rookie of the Year also made the Pro Bowl thanks to 1,168 rushing yards.
However, in year two, he hit a slump and barely made it to 800 rushing yards. He maintained that figure the following year with New England before his career totally fell apart. The father of U.S Open winner Sloane Stephens, John tragically died in a car crash in 2009.