JJ Gabriel and his representatives are in Barcelona for talks about a potential move to the Catalan club.
The 15-year-old is attracting interest from a number of Premier League clubs, as well as Real Madrid, Barcelona, Paris Saint-Germain and Bayern Munich, after he and his team put in a formal request to leave United.
Despite the leadership at United being hopeful they can persuade the young star to stay at the club as he is contracted until the end of the season, it looks more and more likely Gabriel is edging closer to a move away from Old Trafford.
Gabriel and his representatives put in a formal request to be de-registered after the UEFA Youth League tie against Sabah last Thursday - a game United won 5-0 with Gabriel scoring a hat-trick.
Gabriel, who was not named in any of England's youth squads announced on Friday despite representing England most recently at U17 level, has not trained with United since then.
There is a belief - owing to a precedent due to a FIFA loophole - that Gabriel could leave United for a club in Europe once he turns 16 [on October 6] if he obtains a European passport that he could get through either of his parents.
However, any move for Gabriel would be subject to FIFA approval.
United head coach Michael Carrick was asked about Gabriel on Friday and reiterated his view that the matter needed to be handled carefully.
"I think he's a young boy, JJ, and I think it's important that we certainly don't play anything out here," he said.
"I think the exposure and the scrutiny and everything, you've got to be careful and be sensible and think of him as much as anything, so the situation will work itself out, whatever way it's going to work itself out. Making sure he's okay is the important thing."
Merson: Massive blow if Gabriel leaves
Sky Sports' Paul Merson:
"First of all, he's an unbelievable talent. The problem now is with the lad and probably his agents and his family - I don't know him so I'm only thinking from the outside.
"When you're watching Max Dowman at Arsenal and Rio Ngumoha getting given a chance at Liverpool and doing very well, he's probably thinking, 'I should be playing at Man Utd now as well'.
"This is the problem you're going to have with the kids of this day and age. They're so talented that they want to play straight away. When I was playing, it was unheard of at 16.
"It'll be a massive blow for Man Utd. Believe me, this kid is an unbelievable talent. They'll have every club in the world wanting him."