The Red Devils are convinced they can take advantage of uncertainty at Real Madrid to bring him back home to Old Trafford.
And they are prepared to offer £65million plus a player to land the superstar, 28, who is still a hero with the United faithful.
Ronaldo is also understood to be keen on the move.
He has turned down offers from Real Madrid to sign a new deal with only two years left on his current contract.
Real will not give up trying to keep him.
But they have already made contingency plans to bring in Gareth Bale from Tottenham in a switch worth £80m.
They also know that they cannot afford to let Ronaldo’s contract run down and now would be the last chance to get big money back on him.
Ronaldo has put his house up for sale in Madrid and did not play in Real’s final game of the season after falling out with departing manager Jose Mourinho.
The player left United for Madrid in an £80m move in 2009. While he has won a Spanish title and the Copa Del Rey, he has not always been happy at the Bernabeu.
He missed many of his old team-mates at United and kept in touch with Sir Alex Ferguson.
Ronaldo was disappointed when Fergie retired but he still fancies a return.
United have made contact with his representatives.
Sponsor Nike are also in on the deal.
United would make him their joint top earner with Wayne Rooney on £250 000 a week. While Paris Saint-Germain could top that, it is not just about the money for Ronaldo.
The signing would give David Moyes the perfect launchpad for his Old Trafford reign.
Ronaldo has indicated he will not renew his contract at Real Madrid beyond 2015.
Real are determined not to sell the Portuguese this summer but United and PSG remain keen when he does come available.
Ferguson sold Ronaldo to Madrid in 2009, but the 28-year-old has admitted several times in the past few months that he is not totally happy in the Spanish capital.
Portuguese newspaper “A Bola” claimed that the Portuguese star feels he has not been treated well by the Real board despite his excellent performances on the playing field.
“A Bola” also stated that Ronaldo has reportedly been offered a €60 million signing-on fee if he becomes a free-agent at the end of his spell at the Bernabeu and signs for a certain newly-made-wealthy European club.
Madrid President Florentino Perez had said that he expected Ronaldo to end his career at the club, but it now appears he could be looking for a new club in the next two years.
If Ronaldo is true to his word, he would be leaving on a free, not something Madrid are likely to want after having splashed out £80 million on him.
Whether he would move back to United now their manager has changed is yet to be seen, but he could emulate former boss Jose Mourinho by going back to a club he knew appreciated him completely.
United are also considering a move for PSV Eindhoven’s £25m-rated midfielder Kevin Strootman.
The Holland U21 international had been on Everton’s wishlist this year.
Manchester City are ready to step up interest in Ronaldo’s teammate Pepe over the next week.
Meanwhile, Manchester City will issue another statement of intent in their quest to regain the Premier League title by completing the signing of Brazilian midfielder Fernandinho.
A day after Seville announced a deal to sell Spanish winger Jesús Navas to City in a deal that could rise to £22million, the English club are close to confirming another eye-catching acquisition.
City tracked Shakhtar Donetsk Fernandinho all season and the 28-year-old had made it clear he wished to move to the Etihad to improve his chances of breaking into Brazil’s World Cup squad. — The Sun/Mailonline.



