Real Madrid are pushing to sign highly rated Manchester United academy forward JJ Gabriel, with several of Europe's biggest clubs also interested in the 15-year-old.
Gabriel formally notified United earlier this week that he wants to cancel his registration with immediate effect, although the Premier League club can challenge his request.
Barcelona, Paris Saint-Germain and Bayern Munich are also understood to hold firm interest in the teenager, while Chelsea are believed to be among his leading admirers in England. However, Real Madrid's efforts to secure his signature have been described as particularly strong.
The Spanish giants want to recruit Gabriel immediately and place him with Real Madrid Castilla, the club's reserve side.
Unlike reserve teams in England, Castilla compete in Spain's senior football pyramid and currently play in the regionalised third tier. The pathway can provide young players with regular experience against senior opposition.
Thiago Pitarch, who was 18 at the beginning of last season, featured for Castilla against Southampton in the Premier League International Cup in October and went on to make 16 senior appearances during the campaign.
Gabriel, who turns 16 on 6 October, is understood to be unhappy with his pathway towards Manchester United's first team.
Sources close to the youngster believe promises regarding his progression have not been fulfilled.
United, however, maintain that Gabriel had been in contention to become the youngest senior player in the club's history during Wednesday's EFL Cup meeting with Brighton.
Whether he would ultimately have featured remains uncertain after United surrendered a 2-0 advantage to lose 3-2.
The club have not given up hope of convincing Gabriel to stay and are understood to be uncertain about the precise reasons behind his desire to leave.
Gabriel is not currently training with United.
Head coach Michael Carrick, who handed the youngster his senior debut during a pre-season match against Atletico Madrid in Stockholm, stressed the importance of protecting Gabriel given his age.
"I just think we've got to be really careful of the whole situation," Carrick said.
"He's a young boy. He's 15, and for me, definitely, and from a club point of view, looking after our younger players - their welfare, their well-being, their exposure - we've got to be really conscious of that in this situation."
Those close to Gabriel have dismissed concerns surrounding his age and physical development.
They reportedly view Max Dowman's breakthrough at Arsenal as evidence that elite clubs are increasingly prepared to trust exceptionally talented young players. Dowman made his Arsenal debut aged 15 last season.
Any immediate departure from Old Trafford remains complicated by regulations governing the registration and international movement of young players.
Manchester United say Gabriel's registration remains valid until the end of the season, when the youngster will be 16 and a departure could become more straightforward.
However, Gabriel holds an EU passport, meaning a move to a club within the European Union could potentially become possible once he turns 16 on 6 October.
With Real Madrid, Barcelona, Bayern Munich, Paris Saint-Germain and Chelsea all interested, Gabriel's future is shaping up to be a significant battle for one of Manchester United's most highly rated academy prospects.
