Ten former rugby league players, including ex-Great Britain scrum-half Bobbie Goulding, are claiming the sport has left them with brain damage.
Their legal representatives say the players are all suffering from "neurological complications" and they are now planning a legal claim against the Rugby Football League for negligence.
This follows similar action by rugby union players including England's World Cup winner Steve Thompson.
Goulding, who has recently been diagnosed with early-onset dementia, said there was not enough protection for players who had suffered head injuries.
The 49-year-old, who won the Super League and Challenge Cup double in 1996 as St Helens captain, said he had played again within days of being knocked unconscious at least three times in his career.
Former Wales international 48-year-old Michael Edwards, and Scotland internationals, 50-year-old Jason Roach, and 43-year-old Ryan MacDonald, are also part of a test group of 10 players, all under the age of 60, bringing the legal action. All three have also been diagnosed with early-onset dementia.
Their lawyer, Richard Boardman, said he was representing a total of 50 former professional rugby league players in their 20s to 50s, all of whom are showing symptoms associated with neurological complications.
He is also representing 175 former rugby union players, including Thompson, in a separate lawsuit.
Boardman said the legal claim was not just about financial compensation, but making the game safer and getting tested and diagnosed to undertake urgent clinical support.
