The Red Devils and Los Blancos have been locked in negotiations for weeks regarding the Old Trafford goalkeeper, who is understood to have already agreed terms with the La Liga giants.
But United are reluctant to let him leave, even though his contract expires in under 12 months’ time.
The club are reportedly not willing to drop below £28m for the Spaniard, but are ready to entertain the idea of taking both Navas and Ramos in exchange – albeit they may well have to pay a fee with the centre-back alone valued north of £28m..
Real are thought to see this as exorbitant and are against the idea of sanctioning a deal.
Navas could act as a direct replacement for De Gea.
The Costa Rican rose to prominence last summer as he helped his home nation to a shock World Cup quarter-final appearance, which earned him a move to Real from Lavente.
Ramos is considered to be United’s major defensive target, although there are links with Valencia’s Nicolas Otamendi.