Saul Niguez in action for Atletico Madrid
Niguez, 21, has been on United’s radar since last summer and the Red Devils reportedly made a bid for him in January.
The Spanish midfielder has impressed for Diego Simeone’s side this term, scoring seven goals in 32 appearances in all competitions.
His form has attracted further interest from United and has forced Atletico to enter negotiations over fresh terms with Niguez, despite the player still having four years left on his current deal.
However, according to AS, the stumbling block in the talks have been Niquez’s increased wage demands, with Atletico unwilling offer him a salary worth around £3.8m-a-year.
The report goes on to claim Niguez is now considering his options and would be open to a move to the Premier League.
United are prepared to meet Niguez’s £18m buyout-clause and are expected to make contact with Atletico and the player’s representatives in the coming weeks.