The teenage striker chose to stay, despite having offers from Serie A rivals to leave on-loan.
Galli said at an awards function last night: "He must play more, it's obvious.
"He decided to stay at Milan but now the problem is managing him.
"The important thing is to sit down and understand the best thing to do, whether to give him more space in Lega Pro or less minutes in the first team where he would have another growth path."
Galli also stated: "I belong to another generation of football and I am linked to those years that for me remain the best. I was lucky enough to live them, but we still have to look forward, not back... And our boys have to deal with the 'social' that we did not have and that offers a different vision of the world, even that of football."