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Peterson is the easy pick after four games, especially with sophomore quarterback Teddy Bridgewater still working through some ups and downs behind a shaky offensive line.

The Vikings running back leads the NFL in rushing yards with 372, putting him on pace for 1,488 over 16 games. According to ESPN.com's Ben Goessling, a running back hasn't won a rushing title while in his 30s since Curtis Martin in 2004, and only seven backs aged 30 or older have rushed for more than 1,488 yards.

Peterson is still the engine of the Vikings offense. He has 20 or more touches in three of Minnesota's four games, and his 464 combined yards represent almost 40 percent of the team's total offense.

The big plays haven't left Peterson's game, either. He has four rushes of 20-plus yards, including touchdown runs of 43 and 48 yards. He also hauled in a short flip pass from Bridgewater for a 49-yard catch and run in Week 2.

Peterson has had issues in pass protection and holding onto the ball, but those remain minor blips on an otherwise fantastic start for the 30-year-old back. He's averaging 5.0 yards per carry, with two 100-yard rushing games and three touchdowns. What more could you ask for from a back who missed all but one game in 2014?