#4 Matthijs de Ligt

De Ligt is right now one of the best center backs in world football and the Dutchman is only 19 years old. He showed his tremendous potential against Real Madrid, keeping the likes of Karim Benzema and Marco Asensio quiet. The 19-year-old is a ball playing center halve who is very calm and composed.
Already the captain of Ajax, De Ligt has all the potential to be a long term successor to Sergio Ramos. The Dutchman has been attracting a lot of attention from all over Europe, and he definitely will not come cheaply for Los Blancos.
#3 Christian Eriksen

Christian Eriksen is one of the best creative midfielders in world football at the moment. The 27-year-old has been playing consistently well for the Lillywhites. With Luka Modric reaching the end of his career, the Danish international could be a perfect replacement for the Croatian.
Eriksen already has 9 assists to his name in the Premier League and there are still 8 games to go. The 27-year-old is at the peak of his career and he will not come cheap either. But, if signed, Eriksen can take Los Blancos to another level.