If NFL history has taught us one thing, it's that running backs decline rapidly after age 30, which is why Adrian Peterson sounded borderline crazy back in January when he said that he wanted to play for at least five more years.

If the 32-year-old Peterson is serious about playing into his mid-30s, then he might want take some notes from Frank Gore, who has spent the last two seasons laughing in the face of Father Time.

With most of the talk out of Indianapolis this offseason revolving around Andrew Luck and his injured shoulder, it's easy to forget about Gore, who somehow seems to be getting better with age.

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At some positions -- like kicker and quarterback -- you'll see a player improve after their 30th birthday. That doesn't generally happen with running backs, which is why Gore's past two seasons have quietly been two of the most surprising seasons by a running back in NFL history.

When the Colts signed Gore before the 2015 season, they were probably realistically hoping to get one good season out of the running back, who turned 32 in May 2015.

Before Gore arrived, there had only been nine backs in NFL history who had run for at least 950 yards after turning 32. During his first season in Indy, Gore became the 10th player in NFL history to cross the 950-yard mark when he ran for 967 yards.

Heading into the 2016, the odds seemed even more stacked against Gore. As we've mentioned, running backs basically age in dog years once they hit their 30s, so when Gore had his 33rd birthday in May 2016, all signs pointed to an eventual downturn.

That downturn never came. In 2016, Gore rushed for 1,025 yards, becoming just the fourth player in NFL history to hit the 1,000-yard mark after turning 33. To give you an idea of how impressive it is to hit that number at that age, the only three players to reach 1,000 yards after age 33 -- John Riggins, John Henry Johnson and Franco Harris -- are all in the Pro Football Hall of Fame.

That might give you an idea of how underappreciated Gore truly is. He's doing things have only been done by Hall of Famers.

The thing about Gore though, is that even at 33, he's still a threat to catch the ball out of the backfield. In 2016, Gore finished the season with 277 receiving yards. Here's the list of players in NFL history who have rushed for more than 1,000 yards and also added 250 or more yards in one season after the age of 33: Franco Harris, Frank Gore.

That's it.

Not only was Gore's receiving total impressive because of his age, but it was also impressive because it was his highest total since 2010.

At age 34, Gore seems to finally realize that he might be on the back nine of his career with only one or two holes left. The running back originally signed with Indy because he thought Luck and the Colts would give him one last shot at a Super Bowl ring, but now that doesn't look like it's going to happen and Gore seems well aware of that.

"I thought I was one of the missing pieces they needed to get them over the top," Gore recently told CBS 4 in Indianapolis. "Coming in and what it was and going backwards, that's tough."

If Luck's shoulder doesn't heal soon, Gore's run at history might end up being the only highlight of the Colts' 2017 season.

Even if his Hall of Fame career is coming to an end soon, there's no reason to doubt that Gore can defy history for at least one more season. Only four running backs in NFL history have even hit the 800-yard mark after turning 34 -- Marcus Allen, Emmitt Smith, Riggins and Johnson -- and again, all four of those guys are Hall of Famers.

The most amazing thing about Gore's ability to keep playing into his mid-30s might be his durability. The Colts running back hasn't missed a single game since turning 30. As a matter of fact, Gore hasn't missed a single game since 2010, when he was a 27-year-old running back for the 49ers.

Although Father Time might be gunning for him, there's no reason to think Gore can't put together at least one more big season and go down as one of the best running backs in NFL history. If Gore can hit the 800-yard mark in 2017, that would move him up to No. 5 on the NFL's all-time rushing list, a fitting spot for an ageless wonder who has played in at least 14 games in 11 of his 12 career seasons.

If Gore can hit the 1,000-yard mark in Indy this season, he'll become just the fifth player to rush for 1,000 yards or more in 10 different seasons. The only four players to do it so far -- Curtis Martin, Barry Sanders, Walter Payton and Smith -- are all Hall of Famers.

Those four guys are also the only four running backs in NFL history who have rushed for at least 14,000 career yards. With 935 yards in 2017, Gore can join that very prestigious club.