At his peak, Adrian Peterson was the most unstoppable running back in the NFL and was easily one of the best rushers of his generation.

Of course, that was quite some time ago, and Peterson is no longer the dominant halfback he once was, but he is still piling up yards, and he is en route to one heck of a milestone.

Michael David Smith of Pro Football Talk points out that the Washington Redskins back is closing in on Curtis Martin for fifth on the NFL's all-time rushing list, as Martin compiled 14,101 yards on the ground in his career and Peterson is currently at 14,036.

Chances are, Peterson will break that mark some time before the end of the season, and over the last couple of weeks, he has rushed for 99 and 76 yards, respectively, so he could very well hit the 66 yards he needs against the Philadelphia Eagles on Sunday.

On the season overall, Peterson has totaled 718 yards and three touchdowns while averaging 4.3 yards per carry.

The 34-year-old joined the Redskins in August 2018 at a time where it looked like his days of being a heavy usage running back were over.

Peterson split the 2017 campaign between the New Orleans Saints and Arizona Cardinals, finishing with just 529 yards and a couple of scores in 10 games, registering 3.4 yards per attempt.

However, Peterson revitalized his career in his first season with Washington last year, recording 1,042 yards while reaching the end zone seven times on the ground, posting 4.2 yards per tote.

Of course, Peterson's best years came with the Minnesota Vikings, where he made seven Pro Bowl appearances, earned four First-Team All-Pro selections and led the league in rushing three times between 2007 and 2016.