On November 29, the Vikings routed the Chicago Bears 36-10 to up their record to 10-1. Brett Favre had 24 TD passes and just 3 interceptions, E.J. Henderson seemed to be rounding into his pre-2008 injury form, Percy Harvin was coming off his first 100 yard game and Viking fans has visions of a Super Bowl title dancing in their heads.

Since then of course, the team is 1-2 thanks to two ugly primetime losses (maybe the Vikes should get a restraining order against Al Michaels), Favre has thrown 3 TD passes, 4 picks and had a soap opera-like feud with the head coach, Henderson’s season has ended with a gruesome leg injury and Percy Harvin has been neutralized with migraine headaches. All of this has left Viking fans with the dull pounding of despair throbbing in their heads.

And on top of all that, Adrian Peterson is having issues.

Peterson’s numbers after 14 games are good, even great – 281 carries for 1,235 (4.4 yard average) and 15 TDs – but, the stud running back hasn’t cracked the 100 yard mark in 5 games and has averaged just 3.2 yards per carry in that span. A consistent homerun hitter in his first two seasons, when is the last time you saw AP break off one of his signature, jaw-dropping runs? Week 1 at Cleveland?

Even with their recent struggles, the Vikings have a far superior passing attack in 2009 than they had Peterson’s first two seasons, so why isn’t the All Pro finding more holes? The obvious answer is the offensive line. The key to stopping Peterson is getting to him in the backfield before he gets a full head of steam and opponents, especially Arizona, have been successful doing that lately.

Both tackles – veteran Bryant McKinnie and rookie Phil Loadholt along with guard Anthony Herrera are playing with injuries and Steve Hutchinson is not playing at the All Pro level he is getting credit for. I am no expert on offensive lineman, but I’ve seen the former Seahawk miss key blocks several times this season.

That’s not the whole story. Peterson just doesn’t have that burst – the extra gear – we’ve seen in the past. Even when he does get into the open field, he doesn’t pull away and take it the distance. Remember the Detroit game last month when Phillip Buchanon caught him from behind? That didn’t happen in 2007 or 2008. What used to be 50, 60 or even 70 yard runs are now topping out in the 25, 30 yard range.

This leads me to one, simple conclusion, Peterson’s ankle and knee issues are more serious than reported. Opposing teams watch the film and know this. This neutralizes the fear factor, the intimidation advantage that a healthy Peterson brings to the game. Instead of playing back on their heels hoping not to end up looking foolish on highlight reels, defenders are swarming at AP like rabid dogs going for the kill.

Brett Favre may be the story of the 2009 season, but it is still up to Peterson carry this team. If the Vikings are going to have playoff success, they must get Peterson right, even if it means sitting him for the last game or two of the regular season. If AP isn’t firing on all cylinders, it will be just another cold, disappointing January for the Purple faithful.