Richard Sherman is right. There's only one way for NFL players to get guaranteed contracts—or really, any other concessions—from league owners. And it doesn't involve asking nicely.

"If we want as the NFL, as a union, to get anything done, players have to be willing to strike," the Seattle Seahawks cornerback told ESPN on Wednesday. "That's the thing that guys need to 100 percent realize.

"You're going to have to miss games, you're going to have to lose some money if you're willing to make the point, because that's how MLB and NBA got it done. They missed games, they struck, they flexed every bit of power they had, and it was awesome. It worked out for them."

If this sounds like Bargaining 101 for Dummies—use the leverage you have to force the outcome you want, duh—well, that's how power works. Heading into its next round of collective bargaining, the NFL Players Association will be exactly as strong—or as weak—as the ability of its members to stand together, withhold their labor, shut the sport down, and take one on the financial chin so that owners, advertisers, and broadcasters take one, too.

Given what happened the last time the union struck a deal with the league, Sherman and his peers may be severely hamstrung. They've been put in a position where the haves and the have-nots might not find common ground.

Look, walking out on work is hard. Especially for football players. They play a brutal sport, and typically have a short window of time to earn what they can before their brains and bodies break. Forming a picket line means giving up money they'll never get back, all so somebody else can make more in the future. It's not particularly surprising that the NFLPA historically has been lousy at it.

That said, the league's current collective bargaining agreement likely makes a potential future strike even tougher. How so? Start with the bottom line. Under the previous agreement negotiated by former union head Gene Upshaw in 2006, players received 59 percent of annual NFL revenues minus a roughly $1 billion set-aside that went directly into owners' pockets; under the current deal negotiated by NLFPA executive director DeMaurice Smith in 2011, players receive 47 percent, minus a similar set-aside.

In other words: players took an 12 percent haircut that former player Sean Gilbert estimated would cost players $10 billion over the ten-year life of the agreement. Former NFLPA executive committee member Sean Morey told VICE Sports that amount could be closer to $15 billion. Whatever the final number ends up being, every dollar clawed back gives owners more resources to ride out a possible work stoppage when the current CBA expires in 2020—and more importantly, saps the union's ability to fill a war chest of its own, something players will need if they're foregoing paychecks.

But that's not the most union-busty thing about it.

It's one thing to end up with a smaller slice of the money pie; sometimes that happens. It's quite another to agree to divvy up that slice in a way that weakens—albeit inadvertently—your own position. And that's what the CBA seems to do, primarily by fostering what former Tampa Bay Buccaneers general manager Mark Dominik told Kevin Clark of The Ringer is "a have-and-have-not league" in which a small number of star veterans earn big bucks while the rest of the labor pool becomes increasingly younger, cheaper, and more disposable.

When the unintended consequences of the CBA may be making your job harder. Photo by Mark J. Rebilas-USA TODAY Sports

Why the divide? According to Clark, franchises have become increasingly adept at structuring player contracts in ways that are "eradicating the NFL's middle class and costing its lower tier much of its leverage"—mostly through language that reduces pay if players get hurt and/or fail to make their teams' 46-man gameday rosters. Former NFL player-turned-injury insurance salesman Nick Grisen told Clark that those two tricks cost players at least $48 million in 2015 and 2016.

However, the primary culprit is how the CBA treats rookies. Before 2011, incoming players were free to bargain with the teams that drafted them; today, they're subject to a wage scale, three-year renegotiation waiting periods, and team contract options that all conspire to suppress salaries. The last top draft pick under the old agreement, quarterback Sam Bradford, signed a contract worth a guaranteed $50 million; by contrast, the first top pick under the current deal, quarterback Cam Newton, received only $22 million guaranteed.

When the NFLPA agreed to limit rookie pay, the idea was that salary savings would end up in the pockets of experienced players. That's exactly what has happened—for a fortunate few. Otherwise, teams have been incentivized to avoid pricey and (presumably) injury-prone veterans, the better to load up on healthy, hungry, cost-controlled youngsters. As Ben Volin of the Boston Globe explains:

Why would a team pay big money to a free agent when it can simply draft a cheaper, healthier alternative and have him locked in to a near-minimum salary for at least three seasons?

While the CBA promises minimum salaries for veterans—$715,000 this year for players with 4-6 years of experience, $840,000 for 7-9, and $940,000 for 10-plus—many times it works against them.

"I've had teams tell me all the time, 'Your guy is a minimum-salary guy, he's too expensive,' " [an] agent said. "I have veteran players that would play for $50,000 if they could."

Last year, the Wall Street Journal reported that after remaining constant over a 17-year span, NFL career lengths were shrinking at an "unprecedented rate"—dropping by about two and a half years from 2008 to 2014. Clark reports that the number of NFL players age 31 or older has fallen 20 percent from a decade ago. Volin notes that in 2016, about half of the league's players were 25 or younger—which means most of them were still locked into their rookie contracts.

The overall result? A star system economy in which the NFL's on-field labor force is split into two castes:

1. A well-paid minority of recognizable veteran players, mostly quarterbacks, who through skill and injury luck have managed to become the league's equivalent of the petite bourgeoisie;

2. A poorly-paid majority of disposable, relatively anonymous short-timers who function as the league's proletariat, grinding and hoping to last long enough to make it into the upper class.

When only one of your is locked into a cost-controlled salary for the next half-decade. Photo by Bill Streicher-USA TODAY Sports

NFL income inequality isn't all bad. Nor is it totally avoidable. The league always will have superstars, as well as third-string special teams fodder.

Still, the unintended hollowing out of a healthy middle class may have severe consequences for union strength and solidarity. Imagine it's 2020. You're Smith or a player union leader, trying to rally your members for a strike—or maybe just imploring them not to cross a picket line, even though their mortgages are going unpaid and their bills are piling up.

How much motivation do star players have to fight tooth-and-nail against a league that's already taking pretty good care of them? Conversely, how many of your rookie scale players want to drag out a work stoppage in which every missed game check represents a significant chunk of all the money they'll ever be able to earn playing football?

For NFL owners, this is the sneaky genius of the current CBA—in fact, I'd be surprised if league negotiators back in 2011 didn't see probable player class stratification as a feature of the deal, not a bug. In 1999, NBA owners took advantage of infighting between star and rank-and-file union members to negotiate a CBA that limited the maximum amount of money any one player could make; in 2011, the league exploited the same divide to slash the players' share of overall NBA revenues by seven percent.

NFL owners aren't strangers to this tactic. When the league and union were battling over allowing free agency in the late 1980s and 1990s, the NFLPA used group licensing revenue to fund a series of antitrust lawsuits against the NFL. In response, a clever league marketing executive named Frank Vuono devised a plan to undercut the union's efforts: convince top quarterbacks to stop assigning their licensing rights to the NFLPA, and instead partner with the league in order to make more money for themselves.