By all accounts, it seemed one of the most ludicrous of "silly season"—and that's saying something.
But as the relatively brief saga rolled on, so did its believability factor. Fans of the Red Devils around the globe began asking themselves, could Kaka really come to Manchester?
The rumour seemed genuine enough for Real Madrid boss Jose Mourinho to address the Brazilian's future not long after the "news" broke.
"Kaka's situation is completely different," he said. "We have no official request for Kaka" (via ESPN).
The situation was acknowledged to be this: Mourinho was willing to loan Kaka to a big European club for a season, with United and Milan first in line.
So why didn't Sir Alex Ferguson bite?
He has always been a known admirer of Kaka, well before the attacking midfielder almost single-handedly took apart his team in the 2007 Champions League semis.
Kaka himself revealed this at the time: "One of my best friends, Anderson, is also there—how can anyone say no? They are the English and European champions and a great club to play for."
But the player joined Madrid that summer for £50 million, and the rest, as they say, is history.
But what if Fergie had pulled the trigger second time around?
Naturally, new signing Shijni Kagawa would have seen his place in the team immediately marginalised.
It would also have been extremely difficult to have included both Wayne Rooney and Robin van Persie in the same lineup as Kaka.
At least in the case of Kagawa, he is better able to play in either a deeper central role or on the flanks, as he often does for Japan at the international level.
There would have been no guarantees regarding Kaka's adaptation to the British game, either. His poor fitness levels and lack of pace would not have been ideal for the fluid 4-2-3-1 system Sir Alex first introduced to Old Trafford last season.
For a team so dedicated in its faith in youth, the signing would have also betrayed the club's faith in players like Tom Cleverley and Danny Welbeck.
Both are by no means finished articles, but Manchester United is not the kind of club that looks to sign world-class players well past their peaks on the cheap.
Oh, and Manchester United would have another £250,000 a week salary on the books—hardly an incentive for the Glazers to sign off on a deal for a player well past his prime.
There are loan deals that are low risk—but this would not have been one of them.
Long term, as well, it would have had no payoff. Shinji Kagawa is the trequartista to lead United into the future; Kaka would merely have complicated matters.
Few could argue with the fact that the £50 million fee Real paid in 2009 for Kaka now looks horrendously inflated; almost on the level of the Torres-to-Chelsea transfer of last year.
Sure, the Brazilian looked decent enough in his first season at the Bernabeu when he wasn't on the sidelines.
But to pine for the player of old, the player who was arguably the best in the world in 2007, would just demonstrate an inability to let go of the past.
Those who were salivating at the mere mention of "Kaka" and "Manchester United" in the same sentence need a reality check.
Unlike Torres, who is two years his junior, there is very little chance Kaka will ever come close to playing the same kind of football that made his name in Italy.
There will always be a percentage who dream of the day they can see their favourite player run out at Old Trafford in the red of United, Kaka or otherwise.
But in reality, more often than not, such longings are better suited to video games and fantasy football.