Over the past week, it has emerged that the 33-year-old could end his nine-year spell with the La Liga giants in order to link up with Italian champions Juventus.
A report has suggested that the Serie A champions want to announce a deal on Saturday and although that remains to be seen, it appears that Turin is the Portuguese international's most likely destination.
According to The Independent, United enquired about the possibility of a reunion with Ronaldo, only to be told that concrete progress had already been made with Juventus.
If a deal goes through, it is expected that Juventus will pay a fee in the region of £88m, with Real making a profit on the £80m that they paid United in 2009.
During his time at the Bernabeu, Ronaldo has scored 450 goals in 438 appearances in all competitions.