EDEN PRAIRIE, Minn. — Adrian Peterson was inside working out while the Minnesota Vikings went through minicamp on a warm Wednesday afternoon.

Any time the NFL MVP is absent from drills, no matter how deep they are in the offseason, there's an unmistakably missing presence even with 89 other players on the roster and dozens of coaches and staffers surrounding the practice fields at Winter Park.

But this is precisely when the Vikings believe they can spare the time for Peterson to rest. The last year and a half, after all, has been quite the whirlwind of pain, grueling work and eye-popping gain.

There's no telling if Peterson will be able to top himself in 2013, after falling 9 yards short of setting the league's single-season rushing record. Given his swift comeback from reconstructive left knee surgery and that brilliant performance last fall, the prospect of similar feats in the future will be automatically routed to the "possible" folder rather than stuck in the "pipe dream" file.

"Last year was a true test for me. And it made me realize that I can be working even harder than I was previously. So, yeah, I've been working extremely hard with that goal of coming back and being better than I was last year," Peterson said earlier this spring. "That's always my mindset: finding ways to improve and coming back better than I was the year before."

After signing Greg Jennings and trading up to draft Cordarrelle Patterson in the first round, the Vikings have a stronger group of wide receivers for still-developing quarterback Christian Ponder. Because of that, they'd like to rely a little less on Peterson this season.

"Adrian will be the first person to tell you: He'll trade in a 2,500-yard rushing season for a Super Bowl ring. It's not imperative that he rushed for 2,000 yards, or 2,500 yards, for us to win. We want to be a balanced attack," coach Leslie Frazier said. "Our offense is always going to run through Adrian, but we want to be able to pass the ball better than we did a year ago."

For Peterson, life is a bit more balanced these days, too. Last summer, his knee rehabilitation was the primary focus. During the winter, he was recovering from sports hernia surgery. Now, he's in normal mode again. So he's added to his off-the-field pursuits, renewing his contract with Nike, and signing up to be a pitch man for Castrol Edge motor oil and the EpiPen emergency epinephrine injector.

The latter product is personal. He found out last year that he's allergic to shrimp, scallops and lobster.

For all the discomfort, monotony and doubt Peterson had to fend off during his rehab, the scariest moment of 2012 came at training camp after finishing off a meal of his favorite foods.

"We had gumbo, so I was very excited. Had a couple bowls. Got back to my room to rest up, and about 10 minutes later I started experiencing some of the symptoms: itchy eyes, swollen throat," Peterson said, adding: "I'm always thinking that I'm superhuman, and there's nothing really that can affect me, but when that came about, it happened so fast. My throat started to close so fast, and my eyes started swelling. I knew not to panic, but I was getting kind of anxious."

Fortunately, head athletic trainer Eric Sugarman was a phone call and a few minutes away. He brought team physician Dr. Joel Boyd and the epinephrine, and Peterson immediately improved. He was taken to the hospital as a precaution. Anaphylaxsis was the diagnosis, and now Peterson carries two injectors with him wherever he goes. Sugarman's staff keeps them on the sideline and in the training room, too.

"He just wants to make sure I have something to do," Sugarman said, smiling.