The youngster has been the subject of interest from a variety of big European clubs but his price has meant many are unable to enter negotiations.
Tuttomercatoweb report that Milan could attempt to mount a large bid in order to sign the defensive player who is capable of playing in both the centre of defence as well as the midfield.
The price for the 22 year old may be a point of difficulty with his club Sporting Lisbon not willing to listen to any bid below €45 million.
Milan have been unwilling to spend big in recent times, having last spent over €20 million when bringing Zlatan Ibrahimovic to the club in 2011, but could break that streak and mount a bid for the Sporting Lisbon player.
The Portuguese international has made 8 appearances for Sporting Lisbon this season, making one assist.