Ruben Amorim's top target gives Manchester United a January dilemma

If you asked Ruben Amorim what position he would like Manchester United to strengthen the most, there is a good chance he would say left wing-back. It doesn't mean he will get one this month though.

United effectively have no transfer budget for permanent signings this month and will have to sell before they can buy. It is a slightly different situation regarding loan deals and free agents, who don't require such an extensive financial hit.

Right now, United are stuck in an odd sense of purgatory. Despite sensational headlines, there is no real threat of relegation this season and there is a growing acceptance Champions League qualification is unlikely. The club have to be seen as moving in the right direction, though the remainder of the campaign almost feels like a disappointing formality, with the upcoming summer rebuild rapidly growing in importance.

Those summer transfer plans will also dictate what United do this month. It is notoriously more difficult to attract players during the winter window, with fewer stars available for transfer and a premium to pay for signing a player midway through a campaign.

United have struggled to recruit a long-term solution at left-back since Luke Shaw arrived at the club. There have been youth team hopefuls like Cameron Borthwick-Jackson and Brandon Williams, and false dawns in Alex Telles and Tyrell Malacia. Diogo Dalot is doing an adequate job filling in there now, just as Ashley Young did when he was repurposed from a winger.

Amorim will hope he only has to buy once to solve the problem position this year, with Paris Saint-Germain star Nuno Mendes the top target for the role. They won a Portuguese title during two years together at Sporting, with the 22-year-old well aware of the tactical demands the head coach would have of him.

There is hope of a deal as well. Mendes is reportedly unhappy with his current contract situation at PSG and is out of contract next year. The interest from United could either grant him an exit route, or give him an improved contract. He hasn't got much to lose right now.

United's tight financial situation makes a move for Mendes this month highly unlikely, though it also poses the dilemma of what they do next. Lecce left-back Patrick Dorgu is viewed as a cheaper alternative, while a deal is progressing that would see Paraguayan teenager Diego Leon arrive at the club in the summer. There is a hope the 17-year-old could be an immediate understudy to a new arrival, though he might need a loan move to help him acclimatise to European football at such a young age.

With wing-back viewed as such a key position in the squad, United must weigh up whether it is best to sign someone as soon as possible, or wait until the summer to pursue an even better option there.