As Adrian Peterson left the field last Sunday after fumbling in the first quarter against the New York Giants it appeared the Vikings Pro Bowl running back had just suffered an injury to his left ankle.

It turns out the pain Peterson felt wasn't anything new.

Peterson revealed Wednesday for the first time that he has been battling the ankle problem since the Vikings' 35-14 victory against Arizona on Dec. 14. Peterson said the ankle feels "pretty good" now.

"I've been fighting with this ankle injury the past three weeks," he said. "Going out on Sundays I take a lot of shots in the legs, so it got twisted up on that play, and it was pretty painful (against the Giants)."

Peterson rushed for 76 yards, his second-lowest total this season, against the Falcons and also fumbled twice, losing the ball once. He rebounded to rush for 103 yards versus the Giants but 67 came on a second-quarter touchdown run.

Coach Brad Childress has rested Peterson on occasion during late-season practices, in part because the Vikings hold workouts on an artificial surface, but Peterson did not miss any time Wednesday.

Peterson, the league's leading rusher this season, committed his NFL-high ninth fumble against the Giants, although it was recovered by teammate Jim Kleinsasser. Just as he had done the week before, Peterson carried a football around with him in the locker room in an attempt to focus on ball security.

Asked about playing in his first playoff game Sunday against the Eagles, Peterson said: "It's definitely more special and going in with the focus of, 'Hey, it's win or go home.' So make sure with the preparation, everything is tight."

Edwards out, Williams to return?

Childress said Wednesday there's only a "small chance" that starting left defensive end Ray Edwards will be able to play Sunday. Edwards, who did not practice Wednesday, injured his left knee against the Giants and, according to people with knowledge of the situation, could be sidelined for more than week if the Vikings advance. Brian Robison would start in Edwards' place if he can't go.

Meanwhile, nose tackle Pat Williams did limited work in practice after missing two games because of a broken right shoulder blade. Childress said Williams did individual drills, some running and worked on the blocking dummy in practice. The Vikings will see how his shoulder responds today before they decide the next step.

Williams has said "the plan" is for him to return Sunday but he was told at the time of the injury that he would miss a month, and Sunday will be the three-week mark. Childress stressed he will be cautious with Williams. "This is an injury that he could hurt more, this is not one of those, 'Well, he can't do any more damage, he's going to have to have it fixed anyway,"' Childress said. "That's not true. That's why you don't mask pain. Pain is an indicator."

Interest in Frazier

Childress confirmed that the Detroit Lions called to request permission to interview defensive coordinator Leslie Frazier for their head coaching position. Frazier is scheduled to interview in the Twin Cities next week if the Vikings win Sunday. If they lose, he will travel to Detroit for the interview. Childress said no other teams have called about Frazier, but he expects teams will be interested in him, with St. Louis being the most likely candidate.

"Not because of his name but just because of his body of work," Childress said. "He's a good football coach."

Close relationship

Eagles quarterback Donovan McNabb said he has special relationships with Childress and Vikings quarterback coach Kevin Rogers. Childress served as McNabb's position coach and offensive coordinator as an Eagles assistant from 1999 to 2005.

"Both of us have kind of matured in this league and understand exactly what this league entails for us to do," McNabb said. "We are very good competitors, and we just want nothing but the best for our teams. I think what you are seeing from Brad is a team that has really bought into his philosophy. Him coming in and being a disciplinarian and trying to get the best out of his players."

McNabb called Rogers his "father away from home." Rogers served as McNabb's offensive coordinator at Syracuse and the two remain very close friends. McNabb even endorsed Rogers publicly when Syracuse conducted a search for a new head coach last month.