Adrian Peterson expressed confidence that Robert Griffin III will be able to return to being the player he was before suffering a torn ACL.

The Minnesota Vikings' star, who won the MVP last season when he rushed for 2,097 yards -- 9 shy of breaking Eric Dickerson's single-season record -- after he underwent reconstructive knee surgery, offered a reminder that he wasn't himself at the start of the season, either.

"I got stronger," Peterson said. "With (Griffin), it's going to be week by week. The quarterback position is different. He's not just running the ball -- he's back there going through progressions and trying to find guys and really being on alert. He'll be OK."