Chelsea want to sign 15-year-old American Julian Hall, who last week became the second-youngest player ever to play in Major League Soccer when making his debut for New York Red Bulls.
Hall last month signed a new contract until 2026 but Chelsea, Manchester United, Manchester City, Real Madrid and Bayern Munich are tracking the talented winger.
Chelsea interest started when Hall scored twice against them in an Under-15s Generation adidas Cup match in April.
The Blues have been scouting him since then and have been trying to attract the USA youth international for a trial at Cobham ahead of his 16th birthday in January.
But his new contract with New York Red Bulls means any trial can now be blocked and the MLS side can command a more substantial transfer fee.
New York Red Bulls are expected to put up a fight to keep Hall and can offer him a pathway to Europe in their multi-club model, through RB Salzburg and RB Leipzig.
Hall also has a Polish passport which could ease his passage to Europe at a younger age, with USA and Poland both out to secure the international future of a player regarded as a generational talent.
Chelsea have hoovered up some of the best teenage talents in world football in the last 12 months, spending well over £50million to sign Kendry Paez, Deivid Washington, Angelo, Andrey Santos, Cesare Casadei and Gabriel Slonina.
They are building a multi-club model to match Red Bull's impressive development pathways offered to young players.
Their aim is to have a conveyor belt of talented youngsters available to Mauricio Pochettino the first-team.
