The subject was broached when Ferguson was talking about a possible Champions League match between the Red Devils and Los Blancos. When asked whether he thought Ronaldo would ever return, Ferguson said he doubted it, but would welcome his former star back with open arms.
Here is Ferguson's exact quote, per The Guardian's Jamie Jackson:
I don't see that. I'd love to see that but it's fanciful thinking really. First of all, how much it would take to get him from Real Madrid? And second, I don't think there's any chance they would want to sell him. But you never know. I don't know when his contract finishes. He may want to go to another club at some point in his career and I'd hope he would want to come here.
It's not hard to see why Ferguson would feel that way. Ronaldo is arguably the second-best player in the world behind Lionel Messi and a candidate for this year's Ballon d’Or.
However, Ronaldo should be the one extremely motivated to make this seeming pipe dream happen.
Obviously, the red tape is cavernous. If Ronaldo wanted to end his stay before his contract ended, Manchester United would have to pay a massive transfer fee, one heftier than the $131.6 million Real Madrid paid in 2009.
Ferguson's track record says that's highly unlikely. That means Ronaldo would have to forgo a possible contract extension for the next two years in order to make it happen.
Is it worth it? At least legacy-wise, the answer is an unequivocal yes.
It goes without saying that Ronaldo already has a legendary resume at Old Trafford. In six years with the Red Devils, the Portuguese star marveled audiences and ascended to one of the world's greatest players. United won three Premier League titles and a Champions League crown, as Ronaldo left as one of the most decorated and beloved players in recent club history.
A return in 2015 would be a coronation, as if the prodigal son had finally returned home to finish his career.
Granted, there's no denying Ronaldo's time at Real Madrid has been a rousing success. The club has won titles in La Liga, Copa del Rey and Supercopa with Ronaldo. The star striker also became the fastest to 100 goals in the Spanish League and is beloved by the Real Madrid fans across the world.
However, the fact remains that Ronaldo will always be second fiddle to Lionel Messi. Patrice Evra of Manchester United is one notable person who has spoken out on Ronaldo's behalf, saying that he's not respected in La Liga, per ESPN:
He has done some incredible things for Real Madrid, he broke all the records, but they didn't show him the respect he deserves. When Ronny was here, he got the love from all the players, the manager and the fans. He is a winner. But he likes people to like him. He misses Manchester United because it was his house.
Say what you will about Evra's motivations, but he's not wrong. For as long as Messi is setting yearly records, winning Ballons d’Or and getting head-to-head wins, there will be a glass ceiling on Ronaldo's legacy in La Liga.
And considering Messi is over two years younger than Ronaldo, things are unlikely to change any time soon.
On the other hand, that glass ceiling does not exist at Manchester United. Even in 2015, Ronaldo would likely be unquestionably the best player in the Premier League and would make the Red Devils a yearly championship favorite.
Often, you hear in sports how a player ruined his chance to go out on top. By returning to Old Trafford in a couple years, Ronaldo would find the perfect way to end his historic career.
Two years is a long time to wait, but it's worth it.