Starsport understand discussions are underway with representatives for both Raphael Varane and Joao Mario.
Varane has fallen down the pecking order at Real and has struggled to hold down a starting place since Zinedine Zidane took charge.
United big wigs have sat down to try and thrash out a £30m move.
But while he is open to joining United, the centre-back has made it clear he will pull the plug if Jose Mourinho doesn’t become the club’s next boss.
Varane, who has 28 caps, is close to Mourinho, who signed him from Lens when he was boss of the Spanish giants in 2011.