AC Milan hero Demetrio Albertini has urged management to deal in Rafael Leao.
The striker is a confirmed target for Chelsea.
Albertini said: "For Leao, a fundamental rule applies on the market: you can make a mistake in buying, but you cannot make a mistake in selling.
"Replace (Gigio) Donnarumma, a world-class number one, with (Mike) Maignan who proved to be extraordinary, but right now it's hard to find a footballer around with Leao's quality.
"He, (Sandro) Tonali and (Charles) De Ketelaere are the future of the team."
