Gattuso has not featured regularly for Milan this season and has admitted that he would consider leaving in the January transfer window.
Manchester City are reported to be interested in the 31-year-old midfielder.
“I am not aware that Manchester City is interested in him,” Galliani told Gazzetta dello Sport.
“I have also spoken to (Chelsea manager Carlo) Ancelotti and Rino (Gattuso) is not in his plans.”
Galliani added: “Milan is not a hotel where you can check out anytime you want. Rino (Gattuso) has a contract with Milan and I don’t think he has an agreement with anyone – that’s what he told me.
“Now he has two roads; he can either extend his contract or leave, therefore he’ll take a decision in December, before January.”
