1) Adrian Peterson: The 13-year veteran has the best shot with 13,426 career rushing yards -- he's one of three active running backs who have surpassed 10,000 rush yards, along with Gore and LeSean McCoy (10,820). Since Peterson left the Minnesota Vikings in 2017, he has played in 30 games with the New Orleans Saints, Arizona Cardinals and Washington Redskins, averaging 55.9 rush yards per game. He would need to play 29 more games at that rate to join the 15K club. Peterson, 34, has expressed his desire to play into his late 30s, and he's certainly in good enough shape to do so. He isn't the back he once was, but he has shown flashes over the last two seasons, proving he has plenty left in the tank. Peterson re-signed with the Redskins on a two-year deal this offseason, so he has a real opportunity if he can stay on the field.