The Portuguese is desperate to bolster his squad in the January transfer window.
And, after a challenging summer, he is set to receive some serious backing from Ed Woodward.
Reports have suggested a £100m transfer kitty could be on the cards.
Mourinho was desperate to sign a centre-back in the summer.
Attempts to snare Milan Skriniar, Harry Maguire, Toby Alderweireld, Diego Godin and Jerome Boateng all proved fruitless though.
According to Italian news outlet Calciomercato, Mourinho was ready to turn his attention to Ajax wonderkid Matthijs de Ligt.
However, in another blow to the former Chelsea chief’s transfer plans, De Ligt is ready to move elsewhere.
It’s suggested a move to Juventus is now looking increasingly likely.
La Liga heavyweights Barcelona are also sniffing around but Juve have the upper hand.
Manchester City have also been monitoring his progress but are well stocked at the back.
Former Ajax star Arnold Muhren reckons De Ligt – and his team-mate Frenkie de Jong – would be brilliant additions to the Red Devils’ squad.
“There are two [Dutch] players who are good enough – Frenkie de Jong and Matthijs de Ligt,” he told Omnisport.
“They can play for Man United without any problems.”
Muhren insists De Ligt would solve Mourinho’s defensive woes at Old Trafford.
He added: “At United they’ve tried several centre-backs. Why could De Ligt not play there?
“He proved that he is strong enough. He is still young enough to grow.
“He’d get a lot more experience at United.
“United are still searching for the ideal centre-back. De Ligt would bring light to United.
“And United are assured of a player who can play there for years.”
United lock horns with City in the Manchester derby tomorrow.
Mourinho’s men secured a stunning 2-1 triumph over Juventus in the Champions League earlier this week.