Manchester United say Marcus Rashford has “taken responsibility for his actions” and will be available for selection for Thursday's trip to Wolverhampton Wanderers.
The Athletic reported that Rashford sat out in Belfast on Thursday evening before reporting himself too ill to visit Manchester United the following day.
United says the disciplinary matter has been resolved internally and is now closed.
The 26-year-old will return to training and is back in contention for selection having been left out of the squad for Sunday's FA Cup fourth round win over Newport County.
Rashford attended a meeting with his brother and agent Dwaine Maynard, director of football John Murtough and manager Erik ten Hag in Carrington on Monday, with United keen to find out the truth about last week's events in Belfast.
Sir Dave Brailsford also spoke separately to the United squad on Monday, explaining the INEOS approach to sporting excellence and the importance of standards.
United were informed that Rashford was out and about in the Northern Irish capital on Wednesday evening, but the player also visited a nightclub the following evening, hours before he was due to report to a club training session.
Rashford visited Thompsons Garage nightclub in the Northern Irish capital on Thursday evening and returned to Manchester on a private flight the next morning.
Both Manchester United and Rashford's camp declined to comment when contacted by The Athletic.
United said ahead of Sunday's FA Cup game that Rashford was unavailable due to illness and that he had remained at the Carrington training facilities to continue his recovery. It is understood he trained alone at Carrington on Sunday.
When he was working full-time, Ten Hag persisted when asked to provide further information about the striker's unavailability: “He called in sick. The rest is an internal matter. I'll take care of it.”
In November, the United manager described Rashford's visit to a nightclub after his side's 3-0 defeat in the Manchester derby as “unacceptable”.
“I spoke to him about it. It is unacceptable. He apologized and that was it. For us it is an internal matter,” said Ten Hag.
“He is very motivated to make things right. He is completely with us.
“He made a mistake, but that doesn't mean he doesn't fit in. I see him every day in training, I know what he does.”
Additional reporting: Mario Cortegana
GO DEEPER
After Rashford's nightclub visit, Ten Hag faces another test of his authority
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