The striker was sold to Russian club Anzhi Makhachkala over the summer, but his agent recently suggested that the Cameroonian could return to the San Siro on loan during the Russian league's winter break in January.
Despite those claims, Moratti has said that a switch is unlikely.
"I have nothing to say on this. I read it in the papers, but I do not know anything," he said.
"I have never spoken to Eto'o. I don't think it is right to speak about this move now.
"What is certain is that there is a 90 per cent chance the move will not happen."
Eto'o reportedly became the world's highest paid footballer when he moved to Anzhi, picking up an alleged annual salary of €10m (£8.75m).