If Tennessee and Alabama football fans hoped their coaches would be mortal enemies, they’re going to be sorely disappointed on Saturday.

UT’s Josh Heupel and Alabama’s Kaleb DeBoer are South Dakota natives with a relationship that spans about 20 years.

It goes back to at least the early 2000s, when DeBoer asked to study Heupel’s offense at Oklahoma. Heupel said yes and hosted DeBoer for a visit to the Sooners' football complex in Norman.

“There’s not a lot of us from South Dakota, and I knew of him when I was younger,” said Heupel, explaining his reason for helping DeBoer all those years ago.

Heupel and DeBoer will reunite on Saturday (3:30 p.m. ET, ABC) when No. 10 Tennessee (5-1, 2-1 SEC) plays No. 7 Alabama (5-1, 2-1) at Neyland Stadium.

This Third Saturday in October rivalry is far from their South Dakota roots. But their mutual respect as offensive gurus remains strong.

Kalen DeBoer actually peeked into Josh Heupel's offense twice

DeBoer was coaching at his alma mater, University of Sioux Falls, when he drove to Oklahoma to peek into Heupel’s offense. At the time, Heupel was an assistant coach developing the origins of the system he later honed at Tennessee.

In 2023, when DeBoer was coaching Washington toward a national championship runner-up season, he said he was grateful for Heupel’s help early in their careers. It helped him so much that he went back to Oklahoma a second time.

“There were just some little wrinkles here and there that we pulled from people. One year, we went down to Oklahoma because Heupel was another South Dakota guy,” DeBoer told The Athletic.

“I didn’t really know him, but we knew of each other. So I hopped in the car, went down there and he gave me free rein. I sat in a position meeting. He got me into a room and just started studying, and then he’d answer some of my questions. I went back to Oklahoma in 2011, when Jay Norvell was there (as co-offensive coordinator alongside Heupel), and he was great to me.”

ADAMS Tennessee offense is a mess, but Alabama has problems, too

What did Josh Heupel show Kalen DeBoer years ago?

There’s no way to know if anything Heupel showed him all those years ago has relevance to Saturday’s game. Perhaps only Heupel and DeBoer will recognize that.

DeBoer said he borrowed from several coaches early in his career as a low-paid but highly successful coach at Sioux Falls, which he led to three NAIA national titles.

And Heupel has tweaked his offense with each coaching stop at Oklahoma, Utah State, Missouri, UCF and Tennessee.

“I think everybody’s (offense) continues to evolve from when he first visited us,” Heupel said.

In 2016, Heupel and DeBoer faced off as offensive coordinators when Missouri beat Eastern Michigan 61-21. Heupel’s offense put up 647 yards, and DeBoer’s offense countered with 428 yards.

But that was hardly a good sample for what’s coming between two top-10 teams on Saturday.

They went from South Dakota to national titles

Heupel grew up in Aberdeen, South Dakota. DeBoer grew up in Milbank, about 100 miles to the east.

They were both Minnesota Vikings fans as kids, presumably because Minneapolis is the closest major metropolitan area to Aberdeen or Milbank.

They’re close to the same age. DeBoer is 49, and Heupel is 46.

They were both star players on national championship teams, albeit at different levels of college football.

Heupel was a Heisman Trophy runner-up quarterback who led Oklahoma to the 2000 national title. But he recalls watching DeBoer as a record-breaking receiver who sparked University of Sioux Falls to the 1996 NAIA Division II national championship team.

“Through his coaching career, (DeBoer) is somebody I’ve stayed in contact with at times,” Heupel said. “I’ve got great respect for him for what he’s done throughout his career and how he handles himself.”

What rivalry will be like without Nick Saban

This will be DeBoer’s first Tennessee-Alabama game. Heupel has been through three of them, losing in Tuscaloosa in 2021 and 2023 and winning in 2022.

On that night in 2022, the Vols knocked off Alabama 52-49, which triggered an epic field-storming to cap the signature win of Heupel’s tenure.

But those games were against Nick Saban, a college football icon who’s now retired from coaching. This game will be between coaching contemporaries.

But Heupel said the Tennessee-Alabama game is more important than any coach on either sideline, even a pair of proud South Dakotans.

“This rivalry has been around a long time before Nick Saban was a part of it or before I was a part of it,” Heupel said. “The magnitude of this rivalry is about its historical nature and what it’s meant inside this league.”

Adam Sparks is the Tennessee football beat reporter. Email adam.sparks@knoxnews.com. X, formerly known as Twitter@AdamSparks. Support strong local journalism by subscribing at knoxnews.com/subscribe.

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This article originally appeared on Knoxville News Sentinel: Tennessee's Josh Heupel has shared offense with Alabama's Kalen DeBoer