The Red Devils are keen to wrap up a deal to bring the Dutchman to Old Trafford.
Journalist Ben Jacobs admits that talks are progressing, but that Euro 2024 is delaying the deal.
He stated, per the Manchester Evening News: "The Euros have delayed things a little bit, but it's actually benefited Manchester United, because had Zirkzee not been called up to the Netherlands squad, then Milan might have been able to get it over the line.
"Instead, his participation in the Euros gave Manchester United a window of opportunity, and they're now in advanced talks, and these talks are all on the player's side, so Milan have already intimated that they're prepared to pay the €40 million release clause to Bologna and Manchester United would do the same.
"So that's seen as fantastic value, and it's highly unlikely that either club is going to try and negotiate around that."