The Brazilian club have attempted to sign their former player on several occasions, but all their approaches have been rejected, including the last offer of €8 million.
However, having finally sold star player Neymar to Barcelona, Santos are planning a new assault on Robinho.
With the player no longer a first team regular at San Siro, AC Milan are prepared to negotiate a summer sale and everything suggests he will finally return to Brazil this summer.
The 29-year-old has enjoyed two spells with Santos in the past, making a total of 118 league appearances for the club and scoring 49 goals.
Since joining AC Milan from Manchester City in the summer of 2010, Robinho has managed 22 goals in 85 Serie A matches for the Rossoneri.