The 26-year-old Espanyol man has been one of the star’s of his nation’s World Cup squad so far, performing well to put them on the verge of booking a spot in the knockout stage of the competition with one game to go.
This has attracted the attention of Spurs and United, prompting talk that both sides could move for his signature.
The Red Devils are credited as having a long-term interest in the centre-back, but the Lilywhites are new on the scene.
Mauricio Pochettino is thought to be ready to overhaul his inherited squad, with Michael Dawson rumoured to be a name on his way out of White Hart Lane.
Moreno is seen as a good option, and a defender more suited to the Argentine’s high tempo pressing game.
United are monitoring the situation as they plan for life without Rio Ferdinand and Nemanja Vidic, both of whom will not be a Old Trafford next season.