His form has come and gone while talk of a possible transfer away from the club has swelled (via The Independent).
But his recent cameo performance in the Red Devils' 2-1 FA Cup win over Reading showcased all the potential he has to be a genuine match-winner.
Here are five reasons why Sir Alex Ferguson should consider keeping the Portuguese winger beyond this season.
Nani hasn't been Manchester United's only disappointing wide man this season—both Antonio Valencia and Ashley Young have failed to make much of an impression on the flanks.
The Portuguese international is an important member of the squad, providing depth in a position that has always been key to the way a Sir Alex Ferguson side typically plays.
With Wilfried Zaha's impending arrival in the summer, the Red Devils need for four wingers will be fulfilled.
Ryan Giggs has proven a more than worthy force on the left side of midfield, but it's Nani's ability to play both wings better than any of his teammates that makes him a vital commodity.
There aren't many footballers on the planet capable of winning a game with a single moment of genius, but Nani is one of the few.
It is one of the reasons he has regularly been compared to former Red Devil Cristiano Ronaldo, who also had an aura of danger around him whenever he took to the Old Trafford pitch.
Call it the "X-factor," call it what you will, but Nani can be an explosive player with a blistering shot and a complete bag of tricks in his arsenal.
Naturally it would be ideal if he could be a Ronaldo-esque type of threat every game, but at least he has the potential to do things others can't.
Speaking of potential, many fans of United, myself included, still hold out the optimistic belief that Nani can become the great player he has threatened to be since his arrival at Old Trafford in 2007.
It is surely a matter of consistency that has prevented him from becoming an indispensable member of Sir Alex's preferred starting XI.
Comparing the Portuguese winger with Ashley Young, the latter may be an undeniable workhorse, but he just doesn't have the same God-given talent as his peer.
At 26 years of age, Nani doesn't have long to make the final, but most significant step forward in his career, but it is certainly not too late.
During the past couple of seasons Nani has been Manchester United's premier goal-scoring midfielder.
He hit double figures in both the 2010/11 and 2011/12 season, compared to the nine total Antonio Valencia scored in both campaigns.
Nani racked up 24 assists in the Premier League alone during both seasons, nine more than the Ecuadorian (via EPLIndex.com).
He may seem to cut a frustrated figure at times, misplacing cross after shot after cross, but the numbers provide concrete proof that the Portuguese international is not just one of the most productive wingers at Old Trafford but in the league as a whole.
The fifth and final reason for Sir Alex to resist selling Nani in the summer is the player's dynamism.
Unlike Antonio Valencia, he has a left foot; unlike Ashley Young, he can beat a defender one-on-one and unlike Ryan Giggs, he is quick.
He is the most versatile of the four and the only one who the Scotsman could deploy on either flank and feel confident he would deliver.
Again, it must be acknowledged that Wilfried Zaha is supposed to be capable of all of the above, but there are no guarantees regarding the Crystal Palace phenom who has only played his career football in a lower league.
Nani has proven himself worthy of the hype before, he only needs to iron out the inconsistencies in his game to make the transition from a top quality player to a world class talent.
Do you think United should sell Nani in the summer?