But officials said they thought he could be back on the field early next season.
Trainer Eric Sugarman said Monday the running back's injury includes some damage to the medial and lateral minisci in his knee.
Peterson suffered a helmet-to-knee hit from Redskins safety DeJon Gomes in the third quarter. Sugarman said he will probably have surgery in the next seven to 10 days.
Notable deaths of 2014 [PHOTOS]