The 23 year old Greek international is coming off a superb World Cup, which has garnered him attention from elite clubs around Europe.
Sky Sport Italia report that Juventus are thinking about making a bid for the impressive centre back to stock up their defensive department.
However the Bianconeri know that he will not come cheap with Arsenal, Tottenham and Valencia all ready to be sparked into a bidding war.
Everton have also been tagged as long term admirers of the Greek star, and may enter the race as well.
The 23-year-old has made 13 appearances for the Greece national team since debuting in 2013.