The Portugal star is then keen to go into coaching at the club - which could see him overseeing the progress of his son Cristiano Jr.
The 36-year-old signed a two-year deal with the option of a third year in August when his sensational return to the Premier League was announced.
But both he and United manager Ole Gunnar Solskjaer are confident he will be able to continue playing at the top level until past his 40th birthday.
Ronaldo is then tempted to step into a coaching role at the Red Devils where he feels he developed the most after being signed as an 18-year-old by Alex Ferguson.
And that could then see him guiding Cristiano Jr, who is 11 and has started training at United.
A source said: “Ronaldo has made it clear to everyone he has come back to United to help them win trophies.
“But in his mind he is going to play for them for more than a couple of years.
“He is still at the peak of his physical fitness and loves showing that nothing is impossible.
“He is obsessed with football and knows everything about the game.
“Lots of players have started their coaching career at United so he thinks it could be a good way of starting off the next chapter of his career."
Need a VPN? Or seeking to switch? Then support Tribal Football by clicking here to sign up with our official partners NordVPN. Not only will you receive the best VPN experience, but also great discounts by signing up via Tribal Football. Thanks for your support!