The Real Madrid star looks set to depart the Santiago Bernabeu after almost a decade to complete a stunning switch to the Serie A giants.
Ronaldo will earn over £500,000 a week at Juventus, with the Italian outfit stumping up €100m (£88m) for his services.
But according to The Sun, United are not completely out of the race just yet.
The publication claims chief executive Ed Woodward is working behind the scenes to figure out if the Red Devils can afford to match Juventus’ offer.
Cristiano Ronaldo looks set to leave Real Madrid this summer
Cristiano Ronaldo admitted after the Champions League final he could leave
United are not afraid of matching Ronaldo’s current salary demands.
And the report suggests the 33-year-old will be offered a three-year deal should he decide on an Old Trafford return.
The Sun also claim United are not worried about Ronaldo’s previous relationship with Jose Mourinho.
The pair didn’t always see eye-to-eye in Madrid before the Portuguese’s departure back in 2013.
Cristiano Ronaldo enjoyed six years at Manchester United
United have also been linked with Madrid co-star Gareth Bale and Chelsea winger Willian in recent weeks.
The former would cost the Premier League outfit a considerable amount more than Ronaldo this summer.
But as for Willian, United are unwilling to meet the £70m price tag slapped on him by Chelsea.
Mourinho has already added Fred, Diogo Dalot and Lee Grant to his ranks this summer.