League players are preparing to follow their union counterparts into court over brain injury claims.
And a sports lawyer says it could be the "final straw" for professional league, which may not survive if the action is successful.
As first reported by the Herald, 70 former rugby players could have contributed to a possible group class action, including multiple All Blacks, against the game's authorities for negligence.
The rugby league case concerns British league, and it's hard to judge what any ramifications might be for the NRL.
The Guardian reports that up to 10 former league players have approached Rylands Law, which is also representing former union players such as England World Cup winner Steve Thompson who have been diagnosed with brain injuries. The league players, some who are long retired, are understood to be displaying signs of dementia.
Richard Cramer, from the Leeds-based firm Front Row Legal, believed it would be difficult to prove in court that league was negligent. But he indicated any large payouts for such a financially fragile sport could be catastrophic.
"It may not be able to survive claims of this nature, because it can run into thousands and thousands of pounds," he said.
"This isn't good news financially for the sport and could be the final straw but it clearly can't be brushed aside because of the issues facing the players."
But Cramer, whose firm represents sports, media and business people, appeared to believe the case might struggle.
"There is no clearcut favourite here; I can certainly see it from the claimants' point of view," he said.
"The RFL have treated concussion a lot more seriously over the last few years but the real test is whether any governing body in any sport were always aware of the risks associated with head injuries.
"The most obvious defence would be 'Volenti non fit injuria', which means that when a player goes out on the field, they're aware of the physical nature of the sport they're playing and they consent to playing with the risks associated to it.
"But if there is medical evidence to show these issues and injuries have been caused by playing the game, that's something that cannot be ignored.
"If they chose to ignore them at any stage there's a duty of care issue for sure."
"This is a very real issue and while any challenge will be vigorously defended by the authorities, if it can be proven there has been some sort of negligence, there is certainly a chance the claims could succeed."