In nine NFL seasons, Adrian Peterson has played all 16 regular-season games four times. He did it in 2008 with a career-high 363 carries, as well as 2009 (314), 2012 (348) and last season (327) at age 30.

So what can we assume, carries-wise, if the now-31-year-old freak of human injury and aging stays healthy enough to play all 16 games this season?

First, I asked offensive coordinator Norv Turner Tuesday if he has seen anything indications of Peterson's advanced NFL age.

"From this camp, I have not seen anything," Turner said. "He's got burst. He's got such a quick start and we know he's powerful in breaking tackles and running through. He finishes runs out here. We've all seen him take off and run the length of the field."

When Peterson has played all 16 games, he has averaged 21.1 carries per game. His career average is 19.8 per game. Other great backs in NFL history have broken down sooner under a similar workload. The great Earl Campbell, who averaged 19 carries per game, lasted only eight seasons and was a shell of his prime self by his seventh season.

But Peterson dodges most, if not all, comparisons. For example, he takes much better care of his body than Campbell did. The fields of medicine and athletic trainers also are much more advanced than they were back in the '70s and '80s.

I asked Turner if he'll have to make any concessions based on Peterson's age that he didn't have to make a year ago during Turner's only full season of coaching Peterson. It doesn't sound like that will be the case.

Sure, Turner said he wants to get more work for running backs Jerick McKinnon and Matt Asiata. But that's mostly because Turner expects the offense to increase its first down total and therefore have more plays to run.

"I haven't seen [any indications of Peterson being 31]," Turner said. "Obviously, it's training camp. But he keeps such good care of himself. And we did a good job last year of taking care of him through the season. He doesn't look like he's slowing down to me."