Rumours in Spain claim that the Manchester United are keeping a watchful eye on Spanish Under-21 international Aaron Martin.
Sources have apparently told ESPN that United recently sent scouts to watch the left back in action for his club side Espanyol against Levante in La Liga.
It is understood that United's representatives want to be kept informed of the 20-year-old's progress and any other developments that concern his future at the La Liga club.
The left back position at Old Trafford has been an issue over the last few seasons and still remains an area of the squad that manager Jose Mourinho would ideally like to strengthen.
The Portuguese tactician is also a reported admirer of Barcelona's Jordi Alba and rumours of his interest in Fulham's Ryan Sessegnon continue, but yet no official offer for either player has been made.
Luke Shaw, Daley Blind, Marcos Rojo and Ashley Young have all filled in the troublesome position for the Red Devils in recent times, although none of them have nailed down the role as their own, through injury or lack of form.
On Saturday against Liverpool at Anfield in the Premier League encounter, Matteo Darmian played left-back, despite naturally being more suited to the right side.
Espanyol's Martin signed a new long term contract in January, keeping him in Catalonia until the summer of 2022. This deal also includes a buy out clause of €40m to keep interested clubs in check.
After working his way through from the club's youth ranks and reserves, Espanyol recognise that he has shown enough potential in his 36 first team games that trying to keep him during the forthcoming January transfer window or beyond next summer could prove challenging.
Although the young Spanish defender could be the solution, Manchester United are not the only suitors of this talented footballer. Their blue rivals from across the city of Manchester are also beginning to show an interest, and Mourinho might need to act, sooner rather than later, before Pep Guardiola looks to add to his already impressive weaponry at the Etihad.