By all accounts Vikings running back Adrian Peterson had a phenomenal season.

His 2,097 yards rushing made him only the seventh player in history to top 2,000 yards in a single year, and he missed the all-time single season mark by just nine yards.  All that after having major surgery on his knee during the off season.

He helped turn the Vikings from a three win team a year ago into a playoff team this year, and he's already gone record as saying next season he plans to rush for 2,500 yards.

But are AP's accomplishments tainted in any way?  One former NFL coach is hinting that they might just be.

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Former Pittsburgh Steelers head coach, and current CBS analyst, Bill Cowher says that new defensive rules that don't allow players to lead with their heads or hit the heads of opposing players might just have something to do with "why we're seeing all of these records being broken."

Cowher didn't mention Peterson or his season specifically, but he did say that it is a lot more difficult to play, and coach, defense in the NFL these days because of the new safety measures.

I don't think anyone honestly believes that AP benefited from soft defenses and stricter tackling rules in 2012.  I do think plenty of defenders in the NFL did experience great deal of fear going against Peterson this season, but it had nothing to do with tackling technique; they were afraid of getting run over and embarrassed by one of the best to ever play his position.