Peterson has been limited in practice the last two days because of the injury. He rushed for 92 yards and a touchdown last week against Detroit, and leads the NFL in rushing heading into the Vikings' home opener against the 49ers.
"God willing, I will be out there playing," Peterson said. "Not a big deal at all."
Even with Brett Favre at quarterback, Peterson is the key to the Vikings offense. He draws so much attention from opposing defenses who stack eight or nine men near the line of scrimmage that he opens things up for the passing game. The reigning NFL rushing champion has rushed for 272 yards through two weeks and has already scored four touchdowns.
But Peterson started his press conference Thursday with a joke, which should put Vikings fans at ease.
"Right now, I've probably got a weak back," Peterson said.
When did that happen, Adrian?
"It happened, like, a week back," he deadpanned. "But that's all behind me now."
"I'm comfortable with where he's at," offensive coordinator Darrell Bevell said. "I know he's been working hard to rehab. ... Right now, I think he's going to be OK, but we have to continue to go throughout the week with that."
Starting middle linebacker E.J. Henderson returned to practice after missing Wednesday with a shoulder injury. The Vikings' leading tackler practiced on a limited with pads on, but defensive coordinator Leslie Frazier said he believes Henderson will be fine.
Rookie receiver Percy Harvin, who has scored a touchdown in each of his first two games and is the team's primary kick returner, missed practice with an illness.