Minnesota Vikings running back Adrian Peterson, known for his punishing, downhill running style, admitted Thursday that a hamstring injury he has battled for over a month has caused him to run hesitantly in recent games.

Peterson, whose productivity has slacked off in recent weeks, told Chip Scoggins of the Minneapolis Star Tribune the mental effects of his injured muscle have been greater than the physical ones, but he's ready to move forward.

"I feel like it was definitely hurting a little bit," he said. "I feel like it was more in my mind. It's strange to say that, but I think I was kind of holding myself back, not being able to stretch out and really run. I think I was kind of hindering myself. Now that I'm able to be more relaxed and got a clearer mind, I think I'll be able to go out there and go full-speed."

Peterson said he initially suffered a bruised hamstring four or five weeks back, but the soreness and tightness had increased in recent weeks.

After averaging 105 yards through his first four games, Peterson's output has diminished over the last two weeks. In losses to the Giants and Panthers, he rushed for a combined 90 yards and zero touchdowns. One major factor in the drop-off was a decrease in carries, which fell from an average of 23 in the first four games to just 11.5 over the last two.

The five-time Pro Bowler insisted the decrease in touches is in no way related to his injury, claiming he just informed the Vikings of the issue last week.

"They didn't know anything about it until maybe like last week," he said. "That's when I really felt, okay, I'm starting to feel something now that could slow me down a little bit. I really didn't say anything to those guys until like last week. Just told them there's tightness."

Peterson will try to bounce back against the Packers' third-ranked rushing defense this Sunday.

More from SB Nation NFL

• NFL Week 8 picks: Halfway there | Watchability

• Breaking Madden: The Buccaneers and their 44 Greg Schianos | More

• Geno Smith's golden opportunity | Gang Green Nation

• Fumblr: Celebrating the unbeaten Chiefs

• NFL Power Rankings: We have a new No. 1