The Vikings are not ruling out the possibility of rookie Adrian Peterson returning from a sprained right knee as soon as the Nov. 25 game against the New York Giants. But a renowned orthopedic specialist said Peterson should shut it down for the rest of the 2007 season. "It's not realistic," said Dr. Johnny Benjamin, the chief of orthopedics at Indian River Medical Center in Vero Beach, Fla. "Saying it's a Grade 2-plus (tear) is the doctors trying to give coach Brad Childress and all the Viking faithful some hope." "But it's a torn ligament, and a torn ligament is going to take six weeks to heal. And that's for someone like a doctor or news writer, who doesn't go out there and make cuts like Adrian Peterson obviously does."