Galliani has stepped in to ease concerns over the Italy international.
"I am happy for Cassano, he played well against Malmo and I admire him. I was the one who took him to Milan," Galliani told Sky Sport Italia.
"He still has three years left on his contract with us and we have an excellent attack with him in the team.
"Cassano is a fantastic talent and he was destined to be a Milan player."