McManus has become the first Australian footballer to take legal action against a major sporting body over its handling of career-ending concussions after launching legal action against former club Newcastle. The former NSW winger's career ended prematurely after suffering the last of a series of head knocks against South Sydney in July of 2015.

Doctors subsequently diagnosed McManus with "minor brain damage" and "scarring on the brain", which has resulted in a raft of health issues following his playing retirement. Medicos ordered him to abstain from exercise for six months after he struggled with health conditions, including headaches and mood swings.

The 31-year-old said he hoped his legal case could create changes that would further protect players.

"There could be some ground-breaking things here," McManus told Fairfax Media.

"I'd like to think with the information that is available and things like this [claim], the right action will be taken in the future and it will protect players against things like brain damage.

"It's one of those things where I know players are suffering with things and are probably unaware that concussions are the cause of it.

"It's trauma, it's brain trauma. It creates other issues you may not be aware of.

"You don't want to be in the position where you are the first to do something, but I think things have to change in the game, there's no doubt about that.

"It will be what it's going to be."

McManus made all 166 of his NRL appearances for the Knights and continues to be employed by the club in an off-field role.

"I guess this is an issue about my playing career," he said.

"The club has been great in assisting me through my professional transition. I'm committed to still being part of the place. I love Newcastle, I love the fact that I played for the one club. Obviously the issue is before the court and I can't comment much there.

"I guess it's protecting my future and the future of my family. It's had a significant impact on my life and that's why I've gone down the path I've gone.

"In saying that, the club has been very professional in its approach in the way we're working through this thing together.

"I am committed to make money for the club and present a great position on what sort of a club it is. But this matter was in my playing career."

Knights chairman Brian McGuigan said the parties would continue to work together co-operatively until an outcome was reached.

"He's a good bloke, he's given us great service and we will continue to employ him," McGuigan said.

"We have no axe to grind against him because he is seeking some compensation from us for things he or his lawyers didn't think we did right.

"Rest assured, we are very strict about looking after our players. We love our players and do the right thing by them. We have always done that and will always do that."

The McManus case is one of three potentially game-changing lawsuits under way in rugby league. Former Sharks, Rabbitohs, Dragons and Storm forward Michael Greenfield is suing the Australian Rugby League Commission over a shoulder charge that prematurely ended his career in 2012. And Newcastle forward Alex McKinnon has indicated he will consider legal action against the NRL and Melbourne for the tackle that ended his career and resulted in a catastrophic spinal injury.

The NRL has a set of concussion protocols in place that are being reviewed as new updates in research and technology become available. Leading brain surgeon Dr Richard Parkinson has been in discussions with head office about using small impact sensors behind a player's ear to curb the confusion about the long-term impacts of concussion.

The girlfriend of former player Chad Robinson, Rani Morris, said the former Eels and Roosters forward believed his depression was triggered by the multiple head knocks suffered during his playing career.

"He often wondered if his mental illness was brought on by head injuries from being tackled head-on over the years and he had struggled with depression for years," Morris told News Corp after Robinson was found dead in a crashed car in December.