The NFL superstar tells TMZ Sports, with teams not having preseason games and not practicing nearly as much due to COVID-19 protocols ... he believes his career has been extended.

In fact, Peterson says the lack of wear and tear put on his legs this season might allow him to play until he's 40 now!!!

"It actually took a lot off the body," the Detroit Lions running back said of the NFL's schedule this year. "Because we really didn't have a real training camp or OTAs or minicamp or anything like that."

"So, in hindsight, it really kind of allowed me to be a lot fresher."

Peterson -- who had told us back in June he was aiming to play 4 more years -- added, "Maybe it's five years now!"

The 35-year-old is still going strong regardless of the unique schedule ... he's rushed for 389 yards and 2 TDs this season -- and he's been solid every time the Lions have called his number.

And, Adrian's hoping that continues on Thanksgiving against the Houston Texans ... especially because he's doing some really cool charity work for the holiday.

Peterson tells us he and his foundation have partnered with The Athletes’ Corner to donate 100,000 meals to a local food bank in Detroit to help those in need.

To raise awareness for the situation, Peterson says he's going to be rockin' some custom kicks for the Turkey Day game against the Texans -- and check the spikes out ... they're AWESOME!!!