Newcastle prop David Klemmer has been stood down by the Knights after he was issued with a show-cause notice "relating to on field disciplinary matters" during Sunday's 24-10 NRL loss to Canterbury.
It is understood Klemmer, who was not included in the 22-man squad to face the Wests Tigers on Sunday, allegedly abused a club trainer and refused to be substituted.
The Knights have not put a timeframe on when the prop may return to action.
The former Australian representative was recently linked with a move to Parramatta.
The Klemmer development comes after Newcastle coach Adam O'Brien conceded he may have come across as an "egomaniac" after a "poorly-articulated" press conference following Sunday's defeat.
Newcastle's home record is 2-8 this season and, after the loss, O'Brien spoke of his track record of reaching four grand finals an assistant at the Sydney Roosters and Melbourne before getting the Knights job.
The 44-year-old, who took the Knights to the finals in 2020 and 2021, is currently coaching a side running 14th and on Tuesday moved to clarify his comments.
"I'd like that (press conference) back," he said.
"It looks like I'm an egomaniac but that wasn't the message.
"I was trying to talk to the supporter who sits on the hill who must be wondering if they practice defence. Do they do tackle technique at training? Are they fit and tough?"
O'Brien said his side had similar intensity to the Storm and the Roosters at training .
"I didn't want to come across as taking the accolades and success of those clubs. Trent (Robinson) and Craig (Bellamy) built their clubs, I just worked there," he said.
"We're not there yet and my number one job on this earth right now is to get his team to perform on game day."
O'Brien believes he has the full backing of the Newcastle hierarchy but understands why his future would come under the microscope.
"I live in reality and I'm not stupid," he said. "It's a results-driven business."
He described the Knights' two finals finishes under him as "band-aids on a gunshot wound".
The Knights coach said he had made mistakes during the club's pre-season training and said Newcastle's turnover of players in the spine positions was cause for their poor run of form.
"We missed about four weeks of pre-season (due to COVID-19) but at the end of the day that stops with me," he said.
"I need to make sure that we're driving a really hard pre-season - that's the bit that I regret the most - and I've got to make sure I get this one right."
