The McManus case - the first of its kind in Australia - was back in the NSW Supreme Court on Friday. The former NSW winger is seeking damages, costs and interest after claiming the Knights should have forced him into retirement. He alleges their failure to do so caused him permanent brain damage.

McManus' barrister, Christopher Barry QC, on Friday submitted an amended statement of claim to Justice Ian Harrison that, if accepted, changes his client's case dramatically on a number of fronts.

After an "exhaustive" subpoena process, Barry procured video footage of the alleged incidents and told the court it supported his contention that the NRL's concussion protocols weren't followed.

"We were sent on this wild goose chase (in obtaining evidence) when they knew full well what happened to our man," Barry said.

"And they also knew because, like us, we now have videos of the games.

"We now have videos of the plaintiff stumbling around. It's pretty plain when you actually look at it, what was going on.

"And indeed, Dr [Andrew] Gardner - the NRL doctor - was standing on the sideline watching as this was going on.

"Yet, the plaintiff continued to play until he was put in a condition where he was severely damaged as a result of the continuation of the concussion injuries."

McManus' legal team also allege they now have evidence that the Knights knew the dangers of repeated concussions all along and were negligent in allowing the winger to play on.

"We issued a substantial number of subpoenas and loe and behold, what turned up in the subpoenaed material was the fact that the defendants, as they were then and the first defendant now, knew at all times the matters that we contended to have been improperly dealt," Barry said.

"And indeed, they have protocols as to how those matters will be dealt with.

"The case then turned from being a case about knowledge available generally to the fact that they actually knew of the risks and they actually knew what to do to manage it.

"The plaintiff's case is they didn't follow their own protocols."

Dr Gardner had turned down repeated requests to meet with McManus' legal team, the court heard, but Barry said he would be handed a subpoena.

"Your honour will see references to a Dr Gardner in the pleadings," he said.

"Dr Gardner won't speak to us but he was the man retained by rugby league to deal with these matters when it comes to concussive injuries.

"We are going to subpoena him anyway and bring him here."

McManus has also altered the entity he is suing following former Newcastle owner Nathan Tinkler's bankruptcy. With Tinkler's company "deregistered", McManus' legal team has shifted their sole focus to the Wests Group, who they allege wwas also negligent after Tinkler relinquished ownership of the club in June 2014. As a result, the alleged mishandled concussive incidents that occurred under Tinkler's watch will no longer be admitted as evidence.

"The information we got on subpoena demonstrated that the plaintiff's significant brain damage is now being caused by the events that occurred after June 2014," Barry said.

"But of course, what happened when Mr Tinkler sold his company is the new Knights - as we have referred to them in the statement of claim - actually acquired all the knowledge and medical history, employees, doctors, etcetera, of the old Knights. We rely upon that as well."

Justice Ian Harrison is expected to decide whether to accept the new statement of claim next week.

The development comes at a time when three Sydney law firms have outlined plans to launch class actions against the NRL for its handling of concussions. The NFL has already paid out more than $US500 million under the sport's concussion settlement, a figure tipped to reach the $1 billion mark. Unlike the NFL, there is no suggestion the NRL attempted to cover up research on repeated head injuries on players.