The Rossoneri trainer believes the striker will stay with the club and not return to Brazil, while he hopes his side can put in a good performance against Juventus on Wednesday
The former Manchester City striker had been tipped to return to his native Brazil, with Santos reportedly interested in the forward, but Allegri has told reporters that he will be staying with the 2007 Champions League winners.
"We just evaluated the situation. There are some players who would prefer to leave so they can play more often and I just gave my technical opinion, then, the club will make the final decision," he explained to a press conference.
"We analysed the entire team and every single player. Robinho is focused on Milan and he is more than happy to stay, this was also his decision. We need a week before he will be available."
The 45-year-old also called on his team to repeat their performance from the 2-1 win over Siena on Sunday when they take on Juventus in the Coppa Italia on Wednesday.
He added: "We need to repeat our performance from that match, knowing that it could go to extra time and penalties. Last season they were two very entertaining matches and we need to face the match as if it were a final knowing that we are playing in their stadium.
"[Antonio] Conte is doing a great job and the results clearly speak for themselves. He deserves all the praise because he is an excellent coach."