Adrian Peterson has a torn meniscus in his right knee, but Minnesota Vikings coach Mike Zimmer is not ruling the running back out for Sunday's NFL game against the Carolina Panthers.
Peterson went down after a short run in the third quarter of Sunday night's loss to the Green Bay Packers and was unable to put any weight on his right leg as he left the field.
"He's got a torn meniscus," Zimmer told KFAN, the Vikings' flagship station, on Monday.
Zimmer said the timetable for Peterson's return is uncertain.
Many fans who watched Peterson being helped to the locker room on the TV broadcast probably feared a much more serious injury, as he did not put any weight on his leg.
But Zimmer was optimistic after the game, saying Peterson, "might miss a week" only.
"Whatever it was, it calmed down now," Zimmer said on Sunday night.
Peterson tore the ACL and MCL in his left knee in December 2011. He underwent surgery and made a remarkable recovery, starting all 16 games in 2012 and rushing for a career-high 2,097 yards en route to winning the MVP award.
The 31-year-old's injury comes just weeks after the Vikings watched starting quarterback Teddy Bridgewater suffer a season-ending knee injury.