Maurizio Sarri has been assured by Chelsea that Callum Hudson-Odoi will not leave the club in January.
The winger has been widely linked with a lucrative move to Bundesliga champions Bayern Munich, although Chelsea have reportedly turned down a transfer request from the player.
Head coach Sarri is now confident the Blues will keep Hudson-Odoi this month and potentially heading into next season, with the former Napoli boss pleased with the development of the teenager in recent weeks.
"As you know, I don't have the power to sign a new contract [for him]," Sarri told a news conference on Tuesday. "On the pitch, I am very happy with him.
"The club have told me that, in this transfer window, he will remain with us for sure - and very probably in the next, too. I am really very happy with this.
"He is improving. I think he will be the future of our club and English football."
Hudson-Odoi has yet to start a Premier League game but scored against Sheffield Wednesday in the FA Cup on Sunday.
Sarri added: "I am not frustrated [with the speculation] because, on the pitch, he is doing very well.
"I am not happy with the situation but every big team has the same problem. It is not easy to keep these young players. He is one of the best 18-year-old players in Europe.
"The club have told me he is out of the market and probably will be in July."
Asked if Hudson-Odoi is happy with that decision, Sarri replied: "I don't know, but on the pitch he is superb."
Speculation surrounding Hudson-Odoi escalated after he reportedly turned down the opportunity to sign a new contract at Stamford Bridge, but Sarri is still not willing to make promises to the player.
"I cannot do anything. I do not have the power to make him [sign a contract]," the Blues boss said. "It is impossible to promise him he will play every match. It depends on the situation."
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