#3 Toby Alderweireld
Alderweireld is one of the finest centre-backs in the Premier League now, and could be signed to strengthen the vulnerable United defence. Mourinho has struggled to finalise a back 4 for his team, as none of the defenders seem to have provided the assurance and solidity while dealing with the forwards of opposition teams.
They wobbled against Liverpool too as Xherdan Shaqiri got enough space and time to take shots from outside the penalty box, and score a couple of goals.
Alderweireld is an excellent marker, and has very good anticipation and positional sense. He has already played 137 matches for Tottenham Hotspur in 5 seasons, and continues to be a regular starter for them.
He is also a consistent performer for the Belgian national side. Such a player should also be able to guide United’s defenders like Eric Bailly, Phil Jones, and Marcos Rojo, thereby solving their defensive problems. He has already been linked with United.