The player's agent said last week that a move to Santos was very unlikely but Odilio Rodrigues has confirmed that talks are underway.
Rodrigues said: "We are talking to Milan about Robinho, we are evaluating the requests from both Milan and the player. He is always welcome here, but we have to understand whether the operation is possible."
The Brazilian forward has spent some time on loan at Santos during his spell with Manchester City and Rodrigues said it could happen again.
Rodrigues added: "Aside from the dream, there is the reality. We cannot go crazy, so have to keep our feet on the ground. We are talking to Milan, but we're still at the beginning and want to continue."