His answer is as firm as his handshake, which could turn coal into diamonds.

Adrian Peterson: Do you believe you're the best player in the NFL?

"I do," he said.

Who's second best?

"I don't know," he said. "I just worry about who's first."

"Worry" is an interesting choice of words, since, eight days ago, Peterson, the Vikings' star running back, signed a seven-year contract worth up to $100 million.

The Vikings have to worry that injuries and the short shelf life of most running backs will make Peterson's deal less attractive a few years from now. The Vikings should also worry that they just made a franchise-record investment in a player whose position has been devalued by modern passing offenses.

Peterson, if he were the fretting kind, could worry that he will take a tremendous amount of punishment as the focal point of a run-first offense.

Peterson says he doesn't brood. He plans.

In a 1-on-1 conversation by his locker this week, Peterson acknowledged that his body is now a vault as well as a temple, so he's assembled a team of professionals to free his mind and tune his muscles.

"I probably have six or seven people who work for me," he said. "I've got my massage therapist, my nutritionist, obviously my financial people and my agent, my assistant who takes care of things for me off the field. And me."

Peterson's assignment?

"Making sure everything is in line, in order," he said.

Is he a tough boss?

"I can be," he said.

Has he fired anyone?

"I have," he said. "They just weren't taking care of business the way they should have been."

As a kid in East Texas, Peterson admired Cowboys running back Emmitt Smith, which is like hearing that Eminem grew up idolizing Dean Martin. Same category; different genres.

Smith, a short, quick back who ran low to the ground, rarely took violent blows. Peterson invites them. Smith played behind a massive and powerful run-blocking offensive line in Dallas, with an elite quarterback and productive passing game. Peterson enjoyed one season with Brett Favre at his best, and otherwise has had to make do with journeymen at the game's most important position.

Peterson knows he is the Vikings' most important player, and he knows that defenses are aware of this, too. Every question about his health and durability is met with pride and optimism.

"I feel great," he said. "I mean, great. It's all about being a professional and taking care of your body. Getting in the cold tub, getting your treatments, doing the little things that really make a difference. I feel like if I continue to do that and deliver the blow instead of taking a hit, I'll be OK."

Peterson is a different kind of superstar. He's supremely confident yet reserved. He revels in the violence of his chosen sport yet is quiet and polite off the field. He could earn hundreds of millions of dollars over the course of his career in salary and endorsements, yet he insists he hasn't celebrated his new contract with Bentleys or baubles.

"No, not yet," he said. "I'm going to let this whole thing digest first. I like my money to stack."

Stack?

"Yeah, that's original," he said. "Let it stack. I've always been that way, since I was young. If my mom or dad wants something, I've got 'em. But me, I'm pretty good. I'm comfortable where I'm at. I'll let my money stack up and make some smart investments, and build it up."

His yards are stacking up, too. One game into his fifth season, he has rushed for 5,880. At 26, Peterson has reached the prime of his career with good health and guaranteed wealth.

What remains unknown is whether a modern-day NFL team can win a championship while relying on a running back, even a great running back.

"Yes, it's possible," Peterson said. "Anything is possible. When you have the best player and you're surrounded by a good cast -- offensively, defensively and special teams -- then the odds are with you.

"You can get it done."

Jim Souhan can be heard Sundays from 10 a.m. to noon and weekdays at 2 p.m. on 1500ESPN. His Twitter name is SouhanStrib. • jsouhan@startribune.com