Running back Adrian Peterson signed a six-year contract extension with the Minnesota Vikings on Saturday.  How long will Peterson remain an elite running back through?

Adrian Peterson agreed to a contract extension with the Vikings worth as much as $100 million with $36 million in guaranteed money.  Peterson will earn $40 million over the first three years of the deal.  Peterson has made it to the Pro Bowl in each of his first four seasons.  Peterson has rushed for 5,782 yards and 54 touchdowns so far in his career.

Peterson has begun the final year of his rookie deal.  The six-year contract extension will keep him a member of the Vikings through 2017.  However, 2017 is more like the year 2030 in running back years.  The average career for an NFL running back doesn't even reach the four-year mark.  Once a running back reaches 30-years of age, his production typically drops off substantially.  Peterson is 26-years old right now.  It'll be interesting to see how long Peterson can perform at an elite level.