Former AC Milan coach Arrigo Sacchi can understand Sandro Tonali leaving for Newcastle United.
The midfielder is set to depart Milan for a fee of 80m.
Sacchi told La Gazzetta dello Sport: "Certain figures, for a club like Milan, are indispensable. But we must not despair.
"You will see that they will bet on young people, perhaps not big names, and they will try to do like Napoli.
"Let's not forget that Napoli won the Scudetto after selling Koulibaly, Insigne, Mertens and Fabian Ruiz, that is the four most famous."