Adrian Peterson underwent successful knee surgery, according to a statement released by Minnesota Vikings head coach Leslie Frazier on Friday. Peterson was placed on injured reserve following last Sunday's win over the Washington Redskins with tears in his ACL and MCL. He now faces an eight or nine recovery process that could jeopardize his status for the opening of the 2012 season.

"We've received word that Adrian underwent successful knee surgery with Dr. James Andrews and is now resting comfortably," Frazier said. " Adrian is in our thoughts, we wish him a speedy recovery and we look forward to seeing him when he returns to Minnesota."

Peterson played in 12 games this season, falling short of 1,000 yards rushing for the first time in his five-year career. The Vikings suffered as a result, going 3-12 on the year with a game against the Chicago Bears still left to play.

For more on Peterson and the Vikings, be sure to head over to the SB Nation blog Daily Norseman.