The conversation took place between the greatest running back of his era and a player who may define the position in his. Last year, Adrian Peterson chatted with Alvin Kamara and gave him contractual advice — a fraught subject for the position they share — that amounted to this: When it comes time for your next deal, stand your ground.

“I remember telling Alvin, ‘Listen, God willing you stay healthy, keep doing what you’re doing, the Saints are going to be paying you a lot of money here soon,’” Peterson recalled last fall. “So when his opportunity comes, he has to understand his value to the team and what he brings to that team. It’s understanding what your value is and not feeling guilty.”

The gap between how running backs would like to be valued and how their franchises view them, though, is only growing larger. On Thursday morning, Melvin Gordon’s agent told ESPN that the running back will demand a trade if the Los Angeles Chargers refuse to rework his contract, which at the moment calls for him to make $5.605 million in the fifth year of his rookie contract, an option year the Chargers picked up.

The coming Gordon-Chargers standoff will be the latest — and certainly not the last — skirmish in the Running Back Wars. Gordon, 26, is trying to use what leverage he has to obtain a new contract now, before he reaches free agency, which has mostly been a source of frustration for running backs. The Chargers, behaving like most NFL teams, want to use up the best years of their star running back without having to carry him for his most expensive seasons, which double as years he is likelier to be both less productive and more injured.

Le’Veon Bell’s year-long holdout in Pittsburgh may have gathered more attention, but Gordon’s threat will be a telling test case for how the league views star backs. The Dallas Cowboys’ Ezekiel Elliott, drafted in the first round the year after Gordon, will be in an identical situation next summer. Kamara is entering his third season, meaning he will have only one year remaining on his contract after this one, too; the New Orleans Saints do not have a fifth-year option, because Kamara was picked after the first round. Joe Mixon and the Cincinnati Bengals are in the same situation.

The problem for Gordon and other star running backs approaching second contracts is how NFL teams treat running backs. The league views them — even the best of them — as interchangeable, plentiful and fragile.

Last year, Gordon gained 5.1 yards per carry — fourth in the NFL among players with at least 150 attempts — while catching 50 passes for 490 yards and scoring 14 total touchdowns. He was a central cog in one of the NFL’s best offenses. And still, per ESPN, the Chargers have not offered him a contract that would place him among Todd Gurley, David Johnson and Bell, the league’s highest-paid running backs.

Is that a sign of what’s to come? NFL teams have been trending away from megadeals for running backs for years. It doesn’t help Gordon’s case that one year after Gurley signed a four-year, $57.5 million extension with the Los Angeles Rams, chronic knee injuries diminished his workload during last season’s run to the Super Bowl and have clouded his future.

The Chargers playing hardball with Gordon is a reflection of how teams think. The Cowboys took Elliott fourth overall a year after they allowed DeMarco Murray to walk in free agency after he led the NFL in rushing. Even at the time, Cowboys Executive Vice President Stephen Jones could envision following a similar pattern with Elliott: Get the most out of him before he suffered the wear and tear NFL backs endure, then move on from him as they moved on from Murray.

“One of our analytics guys said most backs, they deserve to get their money their first four years in the league, and then they trickle off,” Jones said back in 2016. “It certainly doesn’t hurt to be paying him” on his rookie contract.

It remains to be seen how the Cowboys — and other teams with similar decisions — move forward. They could even try to give Elliott the franchise tag, which would keep him on for a sixth year, although Bell showed how delicate and potentially relationship-fraying that can be.

No two situations are the same — the Saints next summer may feel compelled to give Kamara a huge payday owing to his importance in the passing game and his ability to play all three downs. How Gordon’s negotiations and potential holdout unfold may have a major impact.

As Peterson told him, Kamara and his brethren have to understand their value. For running backs, that calculation is only becoming bleaker.

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