And when a player who has bagged an incredible 39 goals already this season comes on the market, it is not a question of will they fit him in, but how.
So with a vast array of attacking talent potentially at their disposal, how will United line-up their team if they re-sign CR7?
Everybody no doubt will have differing opinions, but here is ours...
Rafael Evans Vidic Evra
Valencia Rooney Ronaldo
Clearly this is no simple task, as there are a few big names left out: Wilfried Zaha, Shinji Kagawa, Rio Ferdinand, Anderson, Nani.
Indeed there is no guarantee either Nani or Anderson will be in the squad next season, while Wilfried Zaha could surprise us all by winning a place in the side, but it would have to be on the right in place of Valencia.
Cristiano Ronaldo will no doubt drift inside to the centre to join Van Persie in attack, with Wayne Rooney able to drift left and cover for him in attack and Phil Jones able to cover defensively to support Evra when Ronaldo surges forward.
Shinji Kagawa would also be interchangeable with Wayne Rooney, while Chicharito and Danny Welbeck will no doubt be waiting on their chances off the bench.
This is just one way United could include their former talisman if they bring him back, now let us know how you would do it...
Let us know your XI below...
image: © Gordon Flood