Crystal Palace will deal with Eberechi Eze's coronavirus "lapses" internally while QPR boss Mark Warburton has admitted his club made a mistake in allowing the winger to attend their game on Saturday.
Eze was allowed to sit in the directors' box at Loftus Road to watch his former club face Fulham in the FA Cup despite the current ban on fans and the national lockdown.
The Football Association is understood to be looking into the incident which seems to be the latest in a string involving footballers breaching coronavirus protocols.
"We know the situation that society is facing in this country, we are all very aware of it," said Warburton at a pre-match press conference.
"QPR as a club have stringent protocols in place that we apply very strongly to every single player and staff member.
"On this occasion we should have declined the request. It's as simple as that. We made the error.
"Eberechi is an outstanding character. I can't speak highly enough of him. He made a request, we should have said no.
"On this rare occasion we have made a mistake, it's as plain and simple as that. It will not happen again."
Palace said they did not know that Eze was planning to watch his old team-mates and insisted the 22-year-old, signed from Rangers in the summer, now realises he should not have attended the match.
The Eagles have confirmed they will deal internally with the incident, plus the fact he was pictured not wearing a mask.
A Palace statement read: "QPR have acknowledged they made a mistake in hosting Eberechi Eze in the directors' box at Saturday's FA Cup match against Fulham without our knowledge.
"Whilst we recognise Eberechi's desire to support his former team-mates, he accepts it was an error of judgement to attend the match.
"We were also concerned to see pictures of Eberechi not wearing a mask at certain moments and are speaking to him about these apparent lapses, which will be dealt with internally."
Eze could still face the wrath of Eagles boss Roy Hodgson, who said last week that no further breaches of Government guidelines by his players will be accepted after Luka Milivojevic broke the rules on New Year's Eve.
Palace captain Milivojevic issued an apology after his household mixed with Fulham forward Aleksandar Mitrovic and his family.
There were further breaches of the regulations over the festive period involving Tottenham, West Ham and Manchester City players.
