Manchester United need reinforcements in January if Ruben Amorim is to have any chance of salvaging what has been a disappointing season so far.

The word from United is that there is "no money" to spend in this month's transfer window, meaning any hopes Amorim has of adding to his squad will be entirely dependent on outgoings.

Following Monday night's 2-0 defeat to Newcastle United, the Reds are just seven points above the drop zone. Relegation, as improbable as it may feel to some, is a possibility on current form.

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It is hardly surprising supporters are demanding new additions in this month's window. However, United are not in a position to loosen the purse strings and spend.

Player sales will be needed to strengthen United's chances of adding to their squad. Even if those sales come, you then still have the debate about which positions need strengthening most. You could be forgiven for saying almost every single one of them needs an upgrade.

But, as Gary Neville highlighted in the aftermath of the defeat to Newcastle, it is the wing-back department that United need to add to most. In Amorim's 3-4-3 system, which he has said he will not abandon amid United's ongoing struggles, wing-backs are crucial.

Amad has prospered as the right-sided wing-back but has started each of the last four Premier League matches in attack, meaning Noussair Mazraoui and Diogo Dalot have operated in the wing-back roles. Playing with two full-backs in those positions does not provide United with the attacking thrust they need from those positions, nor does it give them a sense of balance.

"I think if you were starting, you'd have to start with the fundamentals of this system, which is the wing-backs, they hold it together," Neville told Sky Sports.

"If you don't have the wing-backs functioning up and down that are able to attack and defend equally as good, and there aren't many of those around, by the way, because there aren't many teams that play wing-back, then you're going to struggle.

"So you need two quite unique players in those wide areas, and I think that will be the starting point."

In an ideal world, United would have two quick and athletic operators to perform the wing-back roles. Amorim, in a pre-match interview ahead of the clash with Newcastle, admitted Amad could still be an option at right wing-back.

He has been United's best player since Amorim's arrival, and has performed very well at wing-back. However, they have not had the same luxury on the left, meaning it is easy to understand why Neville believes fixing the wing-back roles should be a leading priority this month should funds become available.