AC Milan say they have been left with a “bitter taste in the mouth” after teenage goalkeeper Gianluigi Donnarumma turned down a new contract.
The Italy keeper, 18, now looks likely to leave the club.
Rossoneri chief executive Marco Fassone said the player had made a “definitive decision” not to renew his deal.
“We were taken by surprise, as we had hoped Donnarumma would be the goalkeeper taking Milan into the future,” he added.
“Naturally, the decision leaves a bitter taste in the mouth, but now we have to go forward.”
Donnarumma – whose contract expires next year – broke into the first team as a 16-year-old and has played almost 70 times since.
The player is represented by agent Mino Raiola, who last summer brokered the deal that took Juventus midfielder Paul Pogba to Manchester United for a world-record fee.
“Raiola informed us that Donnarumma has made a definitive decision not to renew the contract with Milan,” Fassone said.
Donnarumma began his career with Milan in 2015, becoming the second youngest goalkeeper ever to debut in Serie A, aged 16 years and 242 days.
He immediately broke into the starting line-up, earning a reputation as one of the most promising young goalkeepers in the world.
He also broke the record as the youngest Italy under-21 player ever to play, aged 17 years and 28 days in March 2016.
Six months later, he made his senior international debut, becoming the youngest goalkeeper ever to appear for Italy, aged 17 years and 189 days.