INDIANAPOLIS – This is not a bad year to be searching for a replacement for one of the greatest running backs in NFL history.

At the NFL scouting combine this past week, top Philadelphia Eagles executive Howie Roseman called this stacked running back class “historic.” Carolina Panthers coach Ron Rivera raved about the variety of skill sets at the position. Vikings General Manager Rick Spielman again trumpeted that it is the greatest group he has ever seen.

“To be honest with you, I can’t remember a year where the draft class at running back is this deep,” he said Wednesday.

A day earlier, the Vikings announced that they would not pick up the 2017 team option for Adrian Peterson, the leading rusher in franchise history. So Peterson this Thursday will officially become a free agent for the first time in his decade in the NFL, though the Vikings would welcome him back at the right price.

“I think this is a good chance for him to go out and test the market and see what his value is,” coach Mike Zimmer said. “I think he understands there’s also a big benefit in finishing your career with one team.”

Regardless of whether Peterson re-signs with the franchise that fell in love with him this time a decade ago, the Vikings will look to the draft to find his replacement, whether that young back will do it in 2017 or share Vikings carries with Peterson for a year or two before taking over for the fading superstar full-time.

Consensus projections have at least three running backs being picked before the Vikings are first on the clock with the No. 48 overall pick in the second round.

After watching Ezekiel Elliott, the fourth overall pick last year, lead the league in rushing while helping lead a Dallas Cowboys turnaround, some NFL teams might be more willing to buck recent trends by using their top pick on an impact back.

Others will point to Jordan Howard, a 2016 fifth-round pick for the Chicago Bears who was second in rushing yards (a chunk of them coming against the Vikings) as the latest example that productive running backs can be found in the later rounds.

In this deep class of backs, filled with record-setting runners and interesting back stories, both team-building philosophies might prove to be successful after April’s draft.

In the meantime, let’s get to know five of the most intriguing backs at the combine.

The next ‘next Adrian’

LSU’s Leonard Fournette is the latest running back prospect to be dubbed the “next Adrian Peterson,” following Trent Richardson and Todd Gurley. So surely Fournette looked up to Peterson as a youngster, right?

“It never dawned upon me to play in the NFL even as a kid,” Fournette said last week, saying he emulated his game after “nobody.”

But it was clear before he set foot on LSU’s campus three years ago that he would eventually be playing in it.

After rushing for 1,953 yards and 22 touchdowns as a sophomore, debate raged about whether Fournette should risk his draft stock by playing or sitting the year out. Fournette chose to suit up as a junior, was hobbled by an ankle injury and eventually skipped LSU’s bowl game so he could get healthy and start preparing for the NFL draft.

Fournette is expected to be a top-10 selection. He impressively ran the 40-yard dash here in 4.51 seconds despite weighing in at 240 pounds. Like Peterson, he may have limitations in the passing game. But good luck trying to tackle him when he’s a runner.

“My motto is ‘Never let one man take you down,’ ” he said. “That’s my whole purpose.”

The Swiss Army Knife

If you watched Christian McCaffrey blow by would-be tacklers during a stellar career at Stanford, you probably won’t be surprised that 5-11, 202-pound dual threat was one of the big winners of these “Underwear Olympics.”

McCaffrey ranked among the top four among his peers in the 40-yard dash, the vertical jump and the 60-yard shuttle. And his time in the three-cone drill, an important one for that position, was one of the best for a running back over the past 10 years here.

Combine those testing results with his stellar production, especially in 2015 when he was a runner-up for the Heisman, and there is no doubt he has a future in the league.

But at what position?

Stanford used McCaffrey, the son of former NFL wide receiver Ed McCaffrey, as a runner out of the backfield, a wide receiver lined up in the slot or on the outside, and as a returner. In 2015, he set an NCAA record with 3,864 all-purpose yards.

“Wherever they put me,” McCaffrey said. “I’ll do anything a team needs me to do.”

The journeyman

Fournette, McCaffrey and Florida State’s Dalvin Cook are widely considered the top backs in this class. In the second tier and possibly in striking distance for the Vikings is Tennessee’s Alvin Kamara, who took a circuitous route to the NFL.

One of the nation’s top recruits in 2013, Kamara picked Alabama but left the program after redshirting in 2013. He spent a year at Hutchinson Community College, a junior college in Kansas that produced Cordarrelle Patterson and fellow Vikings players Shaun Hill and Toby Johnson. And, like Patterson, he resurfaced at Tennessee in 2015.

“It was just a long road, you know?” Kamara said. “From transferring from Alabama, going to junior college — that’s the lowest levels — [but] being true to myself and staying grounded in what I believe in really helped me in the process. Then going to Tennessee and obviously standing right here in front of you guys is definitely a blessing.”

While Kamara received only 210 carries in his two years there because of injuries and the presence of teammate Jalen Hurd, he made the most of them, rushing for 1,294 and 16 touchdowns. He was also a threat catching passes out of the backfield.

He acknowledged teams asked about that long road to Tennessee but said they seemed more concerned about the limited amount of carries after he got there.

“It’s honestly a good thing,” he said. “Of course they wanted to see more production, but the limited amount of carries, I mean, save it for the league.”

The record-setter

Away from the national spotlight at San Diego State, Donnel Pumphrey rushed his way into the record books. In December’s Las Vegas Bowl, he passed former Wisconsin back Ron Dayne to become the leading rusher in Division I-A history, though that’s only because Dayne’s performances in similar bowl games are not counted.

Regardless, 6,290 career rushing yards at the top level of college football is ridiculous.

“It means a lot to me,” Pumphrey said of his all-time record. “But it means more to my teammates and that’s what it was all about with me. I tried to play my heart out for those guys.”

Pumphrey rushed for 61 touchdowns in four collegiate seasons, and had 1,013 receiving yards with five TD receptions, too. But his size could be an issue: He weighed in at 169 pounds at the Senior Bowl and was at 176 in Indy.

At minimum he profiles as a dangerous passing-game back, akin to Darren Sproles, Danny Woodhead and Marshall Faulk, the latter of whom has been mentoring him.

“I feel like I’ll have to gain a couple of pounds,” said Pumphrey, who is 5-8. “But as long as my speed stays fast, I feel like I can compete at the next level.”

The feel-good story

As he sat out most of his junior season at Pittsburgh with a knee injury, James Conner in 2015 mulled whether he would return or head to the pros. Then he learned he had been diagnosed with Hodgkin’s lymphoma.

His career on hold, he vowed to beat cancer and return to the field. He did, playing in Pitt’s season opener nine months later and scoring twice. The 6-1, 233-pound power back kept rolling, bowling his way to 1,092 yards and 16 touchdowns.

Conner said his dream of playing in the NFL was what kept him going. Having run the 40 in 4.65, he profiles as an early-down bruiser, which could make sense in a committee with Vikings speedster Jerick McKinnon.

Still cancer-free, Conner is considered a Day 3 prospect. But he feels winning his battle with cancer gives him an edge.

“I’ve just been through so much and I think I’m more determined than any running back in this class and just willing to make sacrifices and do whatever it takes,” he said.