The Rossoneri sporting director Ariedo Braida has made a check on the highly rated full-back, who could arrive at San Siro as a replacement for Djamel Mesbah.
Santos, 27, has been playing at a very high level over the last couple of years and even made three friendly appearances for Brazil national team.
The left-back is widely tipped to make a move to Europe in the near future, with Milan looking to pounce.
Fabio Santos is valued at around €5 million and he wouldn’t take up a non-EU spot at San Siro considering he holds a Portuguese passport.
He is currently contesting a Club World Cup final with Corinthians as the Brazilian club battle Chelsea for the coveted trophy.
Santos has made a total of 87 league appearances for the Brazilian giants, scoring 4 goals in the process.