It was a Christmas Day conversation between a coach and a devastated player, a coach whose playing career was cut short 25 years ago by the same injury the player now carries with him into an uncertain future.

The two had spoken the night before, on a plane bound for Minneapolis-St. Paul from Washington, D.C. But the coach, Leslie Frazier, felt the need to double back less than a day later with another uplifting message because he remembers the extent to which an NFL player's "mental fortitude" is tested in the first 24 hours following a torn anterior cruciate ligament.

The Vikings coach shared that message publicly on Monday as he and Eric Sugarman, the team's head athletic trainer, went before the media to paint a promising picture that, they believe, realistically includes running back Adrian Peterson returning to his four-time All-Pro form in time for the start of the 2012 regular season.

"Adrian and I talked," Frazier said, "and I told him that he'll be the guy that people will look at and say, 'Wow, look at Adrian Peterson. He's just as good or better than he was before the surgery.' "

According to Sugarman, Peterson also tore the medial collateral ligament, which is common when the ACL is torn. There also was damage to the medial and lateral meniscus but no damage to the posterior cruciate and lateral collateral ligaments, or to the chondral surface, or cartilage, which Sugarman said was a "positive thing for this injury."

Peterson will have surgery in a week to 10 days, once the swelling subsides and his range of motion is restored. The team's hopes are for Peterson to rehab in Minnesota during the offseason. Peterson wasn't available for comment Monday.

Sugarman said most players today are expected to recover from this injury in eight to nine months. The regular season will start about eight months after Peterson has his surgery.

Sugarman also warned people not to compare Peterson to other players who have had this injury.

"I would really like Adrian to stand on his own merit because Adrian, I feel, is very unique," Sugarman said. "If there's anyone that's going to be able to recover from this injury, it's Adrian Peterson. ... Adrian has a great work ethic. Adrian has the DNA to heal quickly, which he has shown in the past. And he certainly will have the desire and the mental toughness to be able to get through the rehab process."

The team's goal is to have Peterson ready for the regular-season opener. If that comes to fruition, the gruesome blow delivered by Redskins safety DeJon Gomes in Saturday's 33-26 victory will have cost Peterson only one game, Sunday's season finale vs. the Bears.

Frazier said the team's offense, which is being built around Peterson, won't have to be changed. He said the team is counting on Peterson's return, adding that backup Toby Gerhart, who had his first 100-yard game (109) on Saturday, has proven he can fill in if Peterson needs a little more time to come back.

Peterson, who went into the regular season with the smile of a man who had just signed a seven-year, $100 million extension, looked understandably sad when seen outside the team's practice facility Monday. Frazier, however, said he sensed by the end of their Christmas Day conversation that Peterson had "begun to move forward" and was "not down in the dumps or feeling sorry for himself."

And unlike Frazier, whose career as a cornerback ended a quarter-century ago in the Bears' Super Bowl XX victory, Peterson's injury has occurred at a time when the marvels of modern medicine have made comebacks commonplace.

"One of the things that Adrian had mentioned to Eric and others, to the fans, was to stay positive because he is going to remain positive," Frazier said. "He is extremely positive about being able to come back and be as good or better than he was before, and that's the Adrian we're all accustomed to seeing. He sets his goals extremely high and he's one of those guys who, when he puts his mind to it, there's no reason to ever doubt that he can't achieve what he really puts his mind to."