The jerseys that hang in Adrian Peterson's locker could be in Canton, Ohio. They belong to Tom Brady and Eli Manning and Christian McCaffery and who knows how many other stars. But it just means that players of that caliber — Super Bowl MVPs, Hall-of-Famers-to-be and the best at their position at the moment — have asked for, and likely received, a Washington Redskins No. 26 in return.

"It's always an amazing feeling when you got guys coming up to you," Peterson said. "They just kind of pay their respects, and maybe request a jersey. I done said yes to about 30 requests this season, and that's not including the guys here in the locker room."

In the past 50 seasons, here are the players who were at least 33, rushed for at least 800 yards and averaged at least 4 yards per carry: Marcus Allen once, and Adrian Peterson twice — each of the past two seasons, both in Washington.

"His 34?" said fellow running back Chris Thompson, whose locker is next to Peterson's. "I compare his 34 to 26 or 27."

It's a reasonable assessment. Peterson came to Washington in the middle of the preseason of 2018 when he was out of work and when it would have been reasonable to next hear from him at his Pro Football Hall of Fame induction. He was available because, in 13 games with three teams over the previous two seasons, he had averaged just 3.1 yards per attempt. Running backs age fast, and he was aging.

Peterson came to Washington only because Derrius Guice, then a rookie, blew out his knee in an exhibition game. Now, Guice is down again; at 22, he's managed to be healthy for five games over two seasons. Peterson, at 34, is still standing.

"I feel like I have a lot left in the tank," he said.

At some point, the tank has to empty. But when will that happen? I was a doubter when Peterson arrived, not just because of those iffy numbers in his final season with Minnesota and then a year split between New Orleans and Arizona, but because of what history tells us about old running backs. Over the previous half-century, the only backs to have gained 1,000 yards at age 33 or older were John Riggins (twice), Frank Gore and Franco Harris. And then Peterson did it for Washington in 2018.

I'm done doubting Peterson, finished putting parameters on what he might do. That's in part because of what we see on Sundays, the running for impossible yards between the tackles, avoiding direct contact, and squeezing out more mileage after contact. But it's also because of what you hear about how he prepares.

"His training is on a different level," Thompson said. "He hasn't even changed anything that he was doing in his 20s."

In the offseason, Peterson invited Thompson to join him in Houston for preparation. In one workout, Peterson jumped in a workout pool. He turned up all the underwater jets to offer resistance. He cranked the underwater treadmill all the way up. And he ran for 20 minutes.

"I tried to do it," Thompson said. "And I could not. I was like, 'How is he able to do this?'"

Peterson has 14,138 yards rushing, and who knows how many more are coming? The list of players who have gained more on the ground in NFL history: Emmitt Smith, Walter Payton, Frank Gore and Barry Sanders. It's why Case Keenum, the journeyman quarterback, said this week:

"I'm going to get to tell my kids I handed off to Adrian Peterson."

And we'll get to say we watched him.