He'll never win the Ballon d'Or, but that's not to say United won't keep winning the titles, writes Goal.com's Sulmaan Ahmad.
There's only one Ronaldo, and it's not the Portuguese winker, but what even his most vitriolic detractors must surely recognise is his outstanding individual ability cannot be replicated or replaced by another player on the planet.
Leo Messi may even be superior, but doesn't offer as many options as a forward and, as an adopted Catalan, is one of the few players that can still be considered truly untransferable in world football.
Who else can wreak so much havoc from either wing? Maybe Franck Ribery, but he is nowhere near the same goal-threat.
Who else can combine the pace, power, skill and goals? Kaka, yes, but he is not so effective from wide areas, nor is he on the market, having also found his way to the Bernabeu, alongside CR7 (or CR9, as it is speculated he will soon be known).
Sir Alex Ferguson, blanking one and all streams of speculation from the mass media, has not even considered 'replacing' Cristiano Ronaldo. Even names as big as Franck Ribery and Karim Benzema, though they may have ended up taking the No. 7 shirt, wouldn't have taken CR7's place.
It seems Fergie is adopting a much more low-key route towards rebuilding for life after Ronaldo. Luis Antonio Valencia was confirmed as the first signing of the summer just yesterday, for a rumoured £16m from Wigan Athletic.
This is on a par with Tottenham signing Wilson Palacios - also from Wigan - for £14m in January, a transfer universally criticised but ultimately vindicated, as the Honduras international hit the ground running at White Hart Lane and added an invaluable dimension to the Lilywhites' midfield.
The same can be expected of Valencia. Sir Alex appears to now be favouring the blueprint of his 1999 treble-winners. That was a team - despite the inclusion of Ronaldo's No. 7 predecessor, David Beckham - that was full of hard-workers and level heads. For all of Beckham's fame, he rarely made a scene with a strop quite like Ronaldo.
Valencia can slot in on one wing and develop into a top class player, but never will he be made a star. Like Carrick, like Anderson, even like Berbatov, he will be subject to squad rotation whenever Sir Alex sees fit, and serve as just one of many weapons in United's armoury. Their only guaranteed starter up front is Wayne Rooney, and even he can end up playing anywhere from centre-forward to either wing, whether he likes it or not.
You can guarantee that Fergie will have not once told Valencia he is Ronaldo's replacement. At least one more player will be signed by the Red Devils this summer as they seek to further substitute for the loss of their star man. Karim Benzema looks to have slipped through their fingers, as Real Madrid moved for the French prodigy after Valencia (that's the club, this time) refused to sell David Villa.
Next on Ferguson's list, if you believe what you read, is Sergio Aguero. Certainly, United could do a lot worse, and El Kun would certainly make a worthy heir to the No. 7. Then again, the least glamorous option, still rumoured to be under consideration at Old Trafford, is Klaas-Jan Huntelaar.
We can't quite even rule out the possibility of Ribery making the move to Old Trafford, although he, like Benzema, has a preference for the Spanish capital, if he is to be released from the clutches of the incredibly bullish Bayern hierarchy.
Whatever happens, replacing Cristiano Ronaldo will not be a simple, like-for-like swapping exercise. Valencia may not quite be in 'youngster' territory any more, but as he is approaching 24 years of age, still has several years ahead of him in which to improve, given the right coaching and the right team-mates. He couldn't ask for much better than Man United, and despite his relatively low profile, the test of time may reveal that United would have struggled to do too much better than Valencia.
After all, this is just the beginning...
