Cruzeiro have confirmed Milan need "only a few details" to complete the deal.
"There are only a few economic details to go, but despite the fact Cruzeiro have tried to keep hold of Gabriel, he will become to all intents and purposes a Milan player from July," director general Mattos told Observatorio de Esporte.
It was already well known that Gabriel had agreed terms to join the Rossoneri as their reserve shot-stopper.
"Gabriel has grown a great deal with us and Milan realised that too. This is why neither Cruzeiro nor the player could say no to such an important opportunity."