4. Neven SubotiĀ
Keeping in mind United's defensive frailties, a new centre-back wouldn't go amiss this January, either. Nemanja Vidic and Rio Ferdinand are now simply too old to be paired together, and when combined, look a liability at the back. Vidic was badly at fault for Sunderland's opener on Saturday afternoon when he miscued his clearance and virtually teed up Craig Gardner, while you can almost hear Ferdinand's knees creaking at 34. Then you have the likes of understudies Phil Jones and Chris Smalling, who simply haven't shown enough consistency to suggest they are sufficient enough cover for the two aforementioned veterans. A new centre-back would help shore up United's leaky defence this winter and there are very few better than Borussia Dortmund's Neven Subotic. Subotic, at 6ft 4, is of the same intimidating frame as Vidic and has a proven track record when it comes to playing at the very highest levels of the game. The Serbian star marshalled Dortmund's defence admirably last season as the Germans reached the Champions League final and was also an instrumental figure in their two, back-to-back Bundesliga-winning campaigns in 2010-11/11-12. United's defence would look much more solid with Vidic paired alongside his compatriot, while Subotic, at just 24, could be the long-term replacement for Ferdinand.