Adrian Peterson was back. That much was clear to Lions coach Jim Schwartz the last time his defense had to face Peterson. That came in Week 4 with Peterson registering his first 100-yard game of the season, a 21-carry, 102-yard effort in a 20-13 Vikings win.

Peterson has since rushed for 625 yards and four touchdowns in his past five games and certainly seems to be getting stronger each week.

"I don't know that he's getting stronger every week," Schwartz said. "I think he was playing at high level right from the opener. When you watched him, it was hard to believe he was, at the time, eight months off of an ACL [injury]. I've never seen anybody come back that way. It usually takes about a year before [guys] are back to themselves. They can get out there and they're not in danger of hurting themselves. But there's definitely a time factor to it. And he appears to have defied all those time frames for all the other mortal people."

Schwartz mentioned how impressed he's been with Detroit rookie receiver Ryan Broyles, who was brought along slowly and now seems to be rounding into form after suffering a torn anterior cruciate ligament of his own in November 2010 while at Oklahoma. But Peterson? He went under the knife on Dec. 30 and yet he's already poised to go over 1,000 rushing yards for the season this weekend.

"He's not just running the ball well," Schwartz said. "He's making explosive runs. I think he's got 14 of them over 20 yards. He's scoring touchdowns for them. He looks the same as he's ever looked. And if you just watched the game tape, you'd never guess he was coming off an ACL in the last game of the season last year."

Peterson's big runs -- he actually has 11 runs of 20 yards or more -- have come against a flood of eight- and nine-man defensive fronts, making his production all the more marvelous.

"That's life in the NFL when you're a marquee back," Schwartz said. "Whoever it's been, Barry Sanders with the Lions here, Jamal Lewis with the 2003 Ravens rushed for 2,000 yards, Eddie George with the Tennessee Titans. You name it. When you're that guy, they're going to load the line of scrimmage and the great ones can still be productive regardless. I think he classifies as a great one."