Adrian Peterson has been diagnosed with a grade 1 high ankle sprain according to Minnesota Vikings head coach Lezlie Frazier. The good news is that the sprain is not more serious. Still, Peterson isn't expected to take part in football activities until Friday of this week, making him questionable at best for Week 12's matchup against the Atlanta Falcons.

Peterson went down awkwardly after a 12-yard run in the second quarter of last week's loss to the Oakland Raiders. He was carted off to the locker room shortly thereafter, eventually returning to the sideline in a t-shirt. An MRI taken Monday revealed the high ankle sprain, an injury that has a tendency to nag players even after they've made it back onto the field.

Peterson was confident Sunday that he would suit up against the Falcons. If he can't, Toby Gerhart would be in line for an expanded role at running back, along with Lorenzo Booker.

For more on the affect of AP's injury on the Vikings, check out the SB Nation blog Daily Norseman.