He was injured during the second quarter of the Vikings' 29-26 loss to the Baltimore Ravens after a reception.
Peterson only carried the ball seven times for 13 yards before leaving the game with the injury. He is second in the NFL in rushing behind Eagles running LeSean McCoy, who ran for a team-record 217 yards in their victory over the Detroit Lions.
"You can't ignore that fact," Vikings coach Leslie Frazier said. "You want to know exactly how severe the injury is, and it helps you make that kind of a decision. So as we learn more about the severity of it, or the lack of severity, then you can make a clear decision about this ballgame and future ballgames in this season."FARRAR: Fantastic finishes by Patriots, Ravens, Dolphins, Eagles highlight Week 14