Adrian Peterson has defied the odds before, and at this point it’s difficult to doubt the reigning MVP’s healing powers.

The superstar running back was upgraded to questionable for the Minnesota Vikings' home matchup on Sunday against the streaking Philadelphia Eagles, despite a nasty foot sprain and a lingering groin injury.

Peterson has little to play for other than pride and the Viking faithful, with the team falling back to 3-9 and no realistic shot at the playoffs. But this is the same player that returned far earlier than expected from a blown out knee and led Minnesota to the postseason with 2,097 yards rushing and 12 touchdowns last season.

According to the Minneapolis Star-Tribune, head coach Leslie Frazier was impressed by his star player’s first practice since the injury on Friday, but didn’t go so far as to guarantee Peterson playing time against the Eagles.

“It was impressive when you consider the early diagnosis,” Frazier said to the Star-Tribune. “He’s unique. Very unique. He’s so different than everybody else when it comes to recovering from injuries.

‘‘We’ve been in situations in the past where you thought he wouldn’t make it and he made it. So it was always in the back of my mind the chance he would make it.”

Frazier might not have a choice if top back-up Toby Gerhart can’t heal up his hamstring in time. Gerhart filled in for three quarters in last week’s narrow 29-26 loss to Baltimore, gaining 89 yards and a touchdown on 15 carries.

Even with Peterson’s apparently superhuman healing abilities, the Vikings also have to question if they want to risk any further injury and the franchise’s future.

Unlike the Vikings, the NFC North rival Detroit Lions are deep in the playoff hunt and have the inside track to their first division title in 20 years. Detroit has lost three of its last four games, and sorely missed the versatile and dangerous running back Reggie Bush with a strained calf in last week’s 34-20 stunner in Philadelphia.

Bush’s status hasn’t been made official yet by the team, but he returned to practice on Friday according to the Lions official injury report. The Detroit Free-Press also reported Bush participated in Saturday’s practice and is likely to play on Monday night against Baltimore.

The eighth-year back is on pace for the second 1,000 yard rushing season of his career, and 621 of his 854 rushing yards this season have come in Detroit victories. Bush’s presence can also draw attention away from the NFL’s second-leading receiver and teammate Calvin Johnson.

Bush has missed two games this year, in which Johnson was able to haul in seven receptions for 115 yards and a score in Week Three against Washington, but a nagging knee injury may have slowed him to three catches for 52 yards against Philadelphia.

In other news, the playoff-hungry Kansas City Chiefs were forced to rule out Dexter McCluster for Sunday’s key AFC West showdown with the Oakland Raiders due to an infection in the wide receiver’s ankle.

According to reports, the Chiefs were originally worried McCluster had contracted MRSA in a small cut on his ankle, but tests ruled the dangerous form of staph infection out. Highly contagious and difficult to completely wipe out, Kansas City would’ve been the second team this year to deal with MRSA after the Tampa Bay Buccaneers.

The Chiefs (10-3) will be down a solid third-receiver as they try to catch Denver for the division lead and maintain their wild card spot. A victory over Oakland would tie Kansas City with Denver at a 11-3 record, but they’ll need the Broncos to lose once more in order to pull ahead after coming out 0-2 in the head-to-head matchup.

McCluster has tallied 46 receptions for 438 yards and one touchdown, and still has the opportunity to surpass his career-highs in all three categories.