Adrian Peterson's braced for more

Vikings running back Adrian Peterson planted his left foot, made cuts as well as a superhero can in his 19th week since major knee surgery and wrapped things up by telling a few dozen reporters that he's on a hellbent beeline toward the Jacksonville Jaguars.

Doubters beware. Jaw firmly set, the four-time All-Pro said he not only plans on playing in that Sept. 9 season opener, he also expects to "be out there full throttle."

"I'm set on what my mindset is," Peterson said Wednesday after a 15-minute workout witnessed by reporters at Winter Park. "People can say what they want to say, I've got my goals. My whole life I've been setting my goals and pushing forward. I've been successful with doing that."

Peterson said he also has been smart and followed doctors' orders not to overdo it since his surgery Dec. 30. Vikings head athletic trainer Eric Sugarman agreed with that assessment.

"He realizes now that there's too much to lose by doing something foolish the past four months and the next four months," Sugarman said. "He's been pretty good. Now you have to pull back on the reins every once in a while and just remind him. But he's been pretty good about it and I'm on the record as saying that he'll continue."

According to Sugarman, surviving the third month after surgery without a setback was critical for Peterson. That's when athletes coming off ACL surgery are most likely to push too hard and tear the new ligament before it's had enough time to strengthen on its own.

Peterson admits the knee felt stronger than it probably was during that third month. But he listened to his medical staff and took the advice of teammate Chad Greenway, who had ACL surgery as a rookie in 2006.

"Chad was telling me, 'Hey, when that third month comes and you start feeling good, you are going to feel you can do more than you need to be doing,'" Peterson said.

"He cautioned me to be careful during that time to really let it rest and don't rush. He knows how I am, too. And just his mindset, he was the same way. That advice helped."

Peterson was cleared to begin cutting this week. That's why the Vikings had Peterson demonstrate some of the drills he's working on during Wednesday's workout, which was covered by NFL Network analyst and Pro Football Hall of Famer Michael Irvin.

Peterson started with a lateral drill in which he had to field a soccer ball being rolled to either side by Sugarman. He also ran circles around a large hoop, sprinted the width of the team's indoor field four times and finished with eight standing jumps to a box that was about three or four feet high. Peterson wore a knee brace for all but the sprints.

Afterward, a winded Peterson guessed he's "over 50 percent, as far as [his usual] cutting and being explosive." He looked in great shape, as usual, but said his conditioning level won't return to regular-season form until the strength and flexibility return to the knee.

As for when he'll be able to return to football activities, Sugarman said there's no set timetable because each player he's ever dealt with has been different.

"You basically just judge it on the guy's function," Sugarman said. "You know he's to the point now where he's really safe to do just about anything. We gradually ramp him up to functional activity and when we get to the point where he's comfortable and has normal strength back to the other side, or better than the other side, and can function as he needs to, then we make that decision."

Sugarman won't predict when Peterson will return, adding that it will be a team decision from General Manager Rick Spielman on down. Of course, the team already knows where Peterson stands on the issue.

"That's just the way I'm wired," Peterson said. "I've been this way since I was young, since I started playing this game at age 7. I always wanted to be the best in whatever I did -- whatever sprints, lifting, whatever. Sixteen years, 17 years of that, it becomes part of you. It's just instilled in me. It's just the way I am."