MINNEAPOLIS -- ESPN's annual #NFLRank project concluded this morning, with the revealing of the top 10 offensive and defensive players in the league, as voted on by ESPN's team of NFL experts. Minnesota Vikings running back Adrian Peterson, who finished No. 3 in the rankings last year, slipped one spot in this year's edition.

Peterson was ranked as the fourth-best offensive player in the NFL, behind Detroit Lions receiver Calvin Johnson (who was No. 1 after finishing No. 2 last year), Green Bay Packers quarterback Aaron Rodgers (who slipped one spot to No. 2) and Denver Broncos quarterback Peyton Manning, who jumped from fifth to third. Peterson still finished well ahead of Philadelphia Eagles running back LeSean McCoy, who came in eighth overall, but at age 29, he'll of course have to beat historical trends to stay in the top four of next year's rankings.

Here's what ESPN Stats & Information had to say about Peterson:

"Peterson has scored at least 10 rushing touchdowns in each of his first seven seasons in the NFL, and his league-high 64 rushing touchdowns during the last five seasons are 19 more than any other player. Peterson has also led the NFL in yards after contact in four of the last five seasons."

That last point is worth keeping in mind, because it reflects just how hard Peterson has had to work to be the league's best running back in recent years. The Vikings' new offense is designed to get Peterson in space more often, reducing the toll on his body and giving him more opportunities to run free. We saw again in the Vikings' preseason finale how much offensive coordinator Norv Turner wants to make use of pulling guards to create alleys on outside runs, and as we discussed earlier this week, Peterson stands to benefit if he's patient enough to follow blocks in that system. That the Vikings ran for 598 yards in the preseason without Peterson should show how effective they can be with him, and he'll get to work a week from Sunday in St. Louis.