Silva joins Sevilla on an initial loan.
It'll be a €5m loan with option to buy at the end of the season for another €30m.
“He is an excellent new signing, a player who is still young and we've made an important investment for him," said Machin in a Press conference.
“Silva is a Portugal international, he can give a strong contribution with his presence in the box and is convinced he can do great things with us. Milan wanted to keep hold of him and he had other offers, but he chose us."