Manchester United said Marcus Rashford had “taken responsibility for his actions” after he was reportedly seen in a Belfast night spot last week and later reported himself ill.
The club confirmed on Monday it dealt with a “disciplinary matter” regarding the England striker.
Rashford was left out of his team’s 4-2 win against Newport in the FA Cup on Sunday, with United saying he was too ill to take part.
Afterward, manager Erik ten Hag said he would deal with the forward following his reported activities in the week leading up to the match.
“Marcus has taken responsibility for his actions. This has been dealt with as an internal disciplinary matter, which is now closed,” United said on Monday. It did not say if he had been fined.
Rashford will be available for selection when United plays Wolves in the English Premier League on Thursday.
Earlier this season, Ten Hag said it was unacceptable that Rashford took part in birthday celebrations after United lost a match against Manchester City.
“I am aware of it and I spoke with him about it,” Ten Hag said in November. “It is unacceptable. I told him. He apologized and that is it.”