The Red Devils look flimsy at the back.
Despite having installed Louis van Gaal as manager and spending over £150m on new players this summer, Manchester United have had a poor 2014/15 campaign so far.
On Sunday the Red Devils held a 3-1 lead over newly promoted Leicester City in their Premier League clash, only to collapse late in the second half to eventually lose 5-3.
One of the main areas for scrutiny after the game was defence and many think van Gaal will have to enter the transfer market once more in the January window to improve things at the back.
Here are five centre-backs the Dutchman could target.
Mats Hummels, Borussia Dortmund
Many Red Devils fans would have been praying their club landed this 2014 World Cup winner this summer, with Hummels seeming to possess everything they are currently lacking.
Despite his lack of pace the 25-year-old is the complete defender, with strength, composure and authority at the back, although whether the Dortmund captain would want to leave the Signal Iduna Park for Old Trafford is doubtful.
Source: Daily Express.