The Brazil international forward, who re-signed for the Serie A giants this month on a reported free transfer from Real Madrid, played in a friendly against Swiss club Chiasso last week before admitting he was lacking match fitness.
"Kaka is in good physical condition," Rossoneri coach Massimiliano Allegri said at Friday's press conference.
"He has trained very well and has shown great enthusiasm. He is lacking some match fitness but I'm sure he will gradually get there."
The 31-year-old Kaka, who left the Santiago Bernabeu after four years in Spain - having joined from Milan for a reported £56million in 2009 - is looking forward to the encounter in Turin.
"I feel like a child about to make his debut," he said. "It will be an exciting match and I will try to stay calm so that I can play at my best."
Allegri, whose side open their Champions League campaign against Celtic next week, will be without the services of injured defenders Mattia De Sciglio, Ignazio Abate and Matias Silvestre.
The Rossoneri are looking for their second win of the new campaign having bounced back from their 2-1 opening-day defeat at Hellas Verona with a 3-1 win over Cagliari last time out.
Rivals Torino, however, are prepared to pull off an upset.
"If I didn't have the conviction that Il Toro could get a positive result against Milan, I wouldn't send my team out on the pitch," Torino coach Giampiero Ventura said.
"We want to put pressure on Milan. This is a stimulating game and I'm curious to see what the result will be."
The Granata, who will be without midfielder Guillermo Rodriguez (knee), won their Serie A opener against Sassuolo 2-0 before losing 2-0 at Atalanta.