Sunday's loss to Liverpool was Manchester United's joint-heaviest competitive defeatManchester United captain Bruno Fernandes did not ask to be substituted towards the end of Sunday's 7-0 defeat by Liverpool, BBC Sport has been told.
Ex-United captain Gary Neville questioned the 28-year-old gesturing to the bench when Marcus Rashford was substituted in the 85th minute.
But Fernandes was said to be after clarification on his positioning after Antony Elanga replaced Rashford.
Fernandes also appeared to push the referee's assistant in the 81st minute as he tried to get the ball back from Trent Alexander-Arnold on the sidelines.
No action was taken by the referee at the time and the incident is not being investigated by the Football Association, whose rules only allow them to get involved retrospectively around decisions not seen by officials.
Martin Cassidy, chief executive of charity Ref Support UK, said it was a "serious offence" and Fernandes deserved "at least a five-game ban".
The assistant put his hand on Fernandes arm before the push and former Premier League referee Dermot Gallagher said he has "mixed feelings" about the incident.
He told Sky Sports: "You don't want a player to be manhandling a match official, but I would suggest the assistant actually manhandles Fernandes more than he did.
"I think once the official does it first, Fernandes is almost like fly swatting, 'get out of my way, I want to get on with it'.
"So while I don't condone it... and I think the referee [Andrew Madley] is in a difficult position, because if he goes across and makes an issue of it, Fernandes is likely to say 'well, he grabbed hold of me first'. It is difficult."
Neville said United's second-half performance was a "shambles" which was "epitomised" by Fernandes, who "has been embarrassing at times".
He added: "That wasn't a captain's performance from a Manchester United player and I am sure Erik ten Hag will deal with that."
Fellow former United captain Roy Keane added: "Fernandes' body language today was nothing short of disgraceful."
On Monday, Rashford said United must ensure the match does not "define their season".
