Centre Back
The best options for a centre-back pairing are Eric Bailly and Victor Lindeloff as time should end for Jones and Smalling, whose errors cost so many matches for Man Utd if not for the presence of De Gea it would be even worse.
Lindelof has been overlooked by Mourinho last season and that could probably change after his performances in the World Cup. Bailly was out most of last season due to injuries. This means the team has no settled or reliable back-pair and they need someone with a commanding figure and posses an aerial threat during set-pieces that have been missing since the departures of Rio Ferdinand and Nemanja Vidic.
The following are some players Man Utd should consider in this department.
Harry Maguire
A towering 6' 4" and a breezeblock-sized forehead he is the type of player strikers will fear to battle against, he can be an immense threat while moving forward during set-pieces, which we all saw how good he can be at setpieces during England's game against Sweden.
Leonardo Bonucci
He is the sort of guy whom Man Utd is missing since the departure of Vidic and Ferdinand, he is commanding, and he has the experience and one of the key figures during his Juventus days Man Utd should consider signing him rather than playing Smalling and Jones.
Another player who is doing rounds linking with Man Utd is Toby Alderweireld he is probably a good addition and had a decent World Cup but it seems Tottenham are demanding too much for him which we consider for that amount of money Man Utd can get a better player than him.