Just weeks after a US appeals court refused to reconsider its decision to approve the NFL’s concussion settlement with former players, two new lawsuits have come along over the same issue. But the new suits do not target the NFL.

Former running back Paul Hornung, now 80, has filed a complaint against the helmet-maker Riddell, while former safety Haruki Nakamura, 30, is suing insurer Lloyd’s of London.

Legal experts tell Yahoo Finance that Nakamura’s suit has a better chance at success. But both are reminders that the ongoing debate over football head-injuries is far from resolved, and both have the potential to shed new light on which parties that do business with the NFL are liable for NFL head injuries.

Class action against the NFL

In April of last year, a judge approved the NFL’s settlement offer in a class-action lawsuit brought by former players who suffered concussions. The deal provides payments for ex-players suffering from a handful of neurological disorders, giving them a maximum award of $5 million if they suffer from ALS (aka Lou Gehrig’s disease). On average, injured players are likely to receive only $190,000, and many are dissatisfied with the figure. But the only option remaining for those petitioning for more is the Supreme Court, which is unlikely to hear the case.

Riddell was named as a co-defendant with the NFL in that same class-action suit, but was not involved in the settlement procedure. The federal judge may still return to Ridell’s role in the lawsuit after all avenues of appeal against the NFL settlement have been exhausted.

Hornungs against Riddell

The complaint from Paul Hornung and his wife Angela is separate from the class action. It accuses Riddell of failing to warn players that its helmets would not prevent head injuries.

“Riddell’s plastic helmet provided no protection for Paul Hornung’s brain,” the complaint reads, “yet players, including Paul Hornung, were led to believe that the innovative helmets would do so.”

Why go after Riddell instead of the NFL? Because in a product liability case like this one, a plaintiff can only go after the manufacturer (Riddell), not the employer (NFL) that uses the product — unless the employer altered the product in some way. Product liability cases assert a so-called “failure to warn” claim; this appeared against Ridell in the class action suit as well.

Hornung’s complaint will hinge on what kind of warning came with Riddell’s helmets. For a strict product liability claim, the plaintiff does not have to prove fraud — only that the product did not have an adequate warning.

“There is no knowledge requirement, and there isn’t even a carelessness requirement,” explains Geoff Rapp, a law professor at University of Toledo specializing in torts and sports. “As long as you can establish that the product is defective, you don’t even need to claim that they knew or should have known. If you can show that the warning was inadequate and didn’t communicate all the dangers, you can win.”

There is precedent for Hornung’s complaint. In 2013 a Colorado jury awarded $11.5 million to the family of paralyzed high school football player Rhett Ridolfi. The jury determined that Riddell was negligent in not warning players and their families of the helmet’s inability to prevent brain injury, and it assessed Riddell 27% of the fault, or $3.1 million. But it did not agree that Riddell’s helmet was defective.

The exact way in which helmets are distributed to players—or were back when Hornung played—may become a key, granular issue in the complaint. Riddell’s responsibility is to put the warning on the product, “in a way that the end user will see the warning,” Rapp says. “Like when you buy a bike for your kid, there’s a decal stuck right on the body of the bike so you can’t possibly miss it. The same applies to the helmet, it needs to have a warning on it or in a place where the players see it. If it goes to trial, I think we will get very specific arguments about the language in the warning. ”

The uncertainty about chronic traumatic encephalopathy (CTE), a relatively new scientific discovery, helps Riddell and makes Hornung’s case a tough one for him. “Obviously you can’t warn about dangers you didn’t know exist,” says Rapp.

Moreover, for a warning to matter it needs to change the behavior of the user, explains Fred Yen, law professor at Boston College. That is: By going after Riddell for inadequate warning, Hornung is basically claiming, “If you had warned me properly, I would have been more careful about where I stuck my head as a football player,” as Yen puts it. “The jury has to believe that if Hornung had been apprised of the danger, he would have behaved differently. They have to buy the idea that Paul Hornung would turn into a restrained wallflower on a football field because he had been warned properly of the potential danger. His case is not an easy case.”

It also hurts Hornung how long ago he played; Riddell can make the argument that his health problems are not solely caused by football.

Nakamura against Lloyd’s

That is in fact the exact argument that Lloyd’s of London made in denying Haruki Nakamura’s insurance claim. The player had taken out his own $1 million policy to protect against injury, and in 2013 he sustained a career-ending concussion. He sought to cash in on his policy, but Lloyd’s denied the claim, stating it was not clear the 2013 injury “solely and independently” led to his current disability.

Now Nakamura is seeking $3 million.

Nakamura’s case may be easier to win than Hornung’s. Unlike Hornung, decades removed from the NFL, Nakamura is only three years removed from the league. He also had one of the NFL’s own doctors confirm the injury. Based on that fact, Yen surmises, “A jury will say, ‘Why the hell aren’t you paying him?'”

Either defendant in these suits, or both, may end up settling. Yen doubts Riddell would: “If I were Riddell’s counsel I might be very reluctant to settle, and tempted to take it all the way to trial, because if they beat Hornung, it prevents other future plaintiffs from suing.” If Riddell does settle, it might motivate other players to sue as well. As for Lloyd’s, regardless of what happens, the firm may decide it doesn’t want to insure any NFL players anymore.

Riddell and Lloyd’s declined to comment on the claims. The NFL also had no comment for this story.

Both of these separate lawsuits have the same end result: to stoke the debate over the existence and extent of CTE. Lloyd’s, by denying Nakamura’s claim, was basically making the same argument Riddell could: That we still don’t know enough and can’t be sure of any liability. “If Riddell chose,” Yen says, “they would not have difficulty finding a credible medical professional to say, ‘We don’t even know for sure if this disease exists; we can’t tell if he’s suffering from CTE or Alzheimer’s.'” Hornung is 80 years old, after all.

All of the ongoing litigation has an ironic negative effect for the league, even though it doesn’t target the league. “The one thing the NFL was hoping to buy from the settlement was moving on from this issue,” Rapp says. “And that isn’t happening. We’re still talking about concussions.”

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Daniel Roberts is a writer at Yahoo Finance, covering sports business and technology. Follow him on Twitter at @readDanwrite. Sportsbook is our recurring sports business video series.

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