Christian McCaffrey became the highest-paid running back in NFL history during the same offseason in which the Los Angeles Rams waived Todd Gurley. Michael Conroy/Associated Press

Nothing explains the complicated state of the NFL running back better than the reaction when a great one gets paid. Christian McCaffrey is the latest to reset the market, which means he is the latest to make everyone queasy about the likelihood that he can offer a good return on the Carolina Panthers’ gigantic investment.

Four years, $64 million? And the extension doesn’t kick in until 2022? Forget that he’s deserving. Forget that, in 2019, he became just the third running back in league history to surpass 1,000 rushing and receiving yards. Forget that he has a preposterous 303 career receptions in his first three pro seasons. While his play easily justifies the fat new contract, we still doubt whether his future production will verify he was worth all the cash. Such is the life of the NFL running back, the position in which accomplishments devolve into concerns about durability. As the depressing data of injury risk mounts, the value of a high-paid back is always in question. In addition, anecdotal and statistical evidence suggests the position isn’t as vital to success as it used to be.

So here comes McCaffrey, trying to reverse the perception. Fittingly, he became the highest-paid running back in NFL history during the same offseason in which the Los Angeles Rams waived Todd Gurley, a former standard-bearer. Gurley, who has a history of knee problems, was cut less than two years after signing a four-year, $60 million deal that included $45 million in guarantees.

Todd Gurley signed a four-year, $60 million deal with $45 million guaranteed with the Rams, who cut him less than two years into the deal. Mark J. Terrill/Associated Press

The website OverTheCap.com, which tracks NFL contracts and analyzes trends, published a detailed look at running back contracts of at least three years since 2011. I won’t go too deep into the numbers, but here was the overwhelming conclusion: Long-term commitments are no bueno. And it’s even worse than imagined.

“Overall teams had an unfavorable outcome about 83 percent of the time with the team overestimating the length of the contract,” Jason Fitzgerald wrote.

So it’s not just boilerplate negativity. Of all the lucrative positions in the NFL, running back is by far the riskiest to make an investment. But McCaffrey is also a new breed of back, a descendant of Marshall Faulk in style, with a modernized approach. Still just 23, he’s as versatile as it gets, and when you put him with Alvin Kamara and Saquon Barkley, the trio could create a new genre of tailback that fits the evolution of football.

By the end of this decade, the pure run-first back will be nearing extinction. The demand will be that all backs must be good pass catchers and true three-down players. There’s already significant movement in this direction, and it increases the value of backs with that skill set.

McCaffrey takes it to another level in that he could truly be a wide receiver if he focused on it. It’s in his blood; his father, Ed, had 565 receptions, 55 touchdowns and earned three Super Bowl rings in his NFL career. In his three seasons, McCaffrey is more than halfway to his dad’s total. He can run between the tackles and fight for tough yards. He’s a touchdown waiting to happen in the open field. He can catch it out of the backfield to make something out of nothing, and he has the potential (which Carolina hasn’t fully unlocked yet) to run just about every route, making him even more of a matchup nightmare.

McCaffrey – along with Kamara, Barkley and younger players aspiring to be them – have a chance to be more than a special subset of running back. They could change the position.

Think about how the tight end, much more of a blue-collar position historically, has added value now that the tight end/wide receiver hybrid has emerged. Think about the growing value of hybrid linebacker/safeties – a reason Clemson’s Isaiah Simmons will be drafted high next week – who can play in space. Similar to basketball, the positional lines are blurring in football because the athletes are changing and becoming more versatile. Football will always be physical, but speed has never been more important.

For running backs to regain their status in the evolved sport, longevity will be as important as skills. Can McCaffrey be the new-school Faulk for 12 seasons? Can Kamara start posting 1,000-yard rushing seasons to complement his 80 receptions for an extended period? Can Barkley, who weighs 230 pounds and might possess the most impressive combination of skills ever seen in a running back, stay healthy? If they dominate the next decade, the game changes for the NFL running back.

Can Ezekiel Elliott fulfill the six-year, $90 million extension Dallas gave him last September? Ron Jenkins/Associated Press

Let’s throw Ezekiel Elliott, who is more traditional in style but still versatile, into the mix as well. Still just 24, he’s on a historic pace. If he stays out of trouble and remains healthy, perhaps he can justify the six-year, $90 million extension Dallas gave him last September. Like McCaffrey, Elliott must defy the recent trend, but he’s another durable, freakish athlete.

McCaffrey hasn’t missed a game in three NFL seasons. Now he’s the face of the Carolina franchise. Cam Newton is gone. Luke Kuechly retired young. The Panthers are rebuilding, and the hope is that, by the time McCaffrey’s extension kicks in, Coach Matt Rhule will have the team in position for perennial contention.

“I don’t look at him as just a running back,” Rhule said of McCaffrey in a radio interview. “We see him as a weapon. He can be a wideout, running back and returner. He’s not a player who you can pigeonhole.”

Rhule and new offensive coordinator Joe Brady must be careful to maximize him as a weapon but not make him a crutch. There’s a big difference. Despite his history of good durability, he can’t continue to carry the ball nearly 300 times and catch more than 100 passes while playing behind a suspect offensive line and with a shaky quarterback. The Panthers have a lot of needs, and it will take multiple seasons to get it right. Until then, they need to be wise about McCaffrey’s workload.

It’s not just important for the Panthers that McCaffrey last. It’s important to the entire running back position. It’s important to the belief that these versatile hybrid backs could increase the value and longevity at the position.