#1 Anderson
The infamous Anderson has become something of a comical figure amongst Premier League fans, with the oft-repeated joke that the Brazilian has more league medals than Steven Gerrard, a joke supposed to be a slight against the England legend, but it's forgotten just how talented Anderson was.
A box-to-box midfielder with stunning vision and silky passing, Ferguson had high hopes for the youngster, seen as a potential successor to Paul Scholes, and he did indeed perform well during his first season; he even scored his penalty in the tense shootout between his club and Chelsea in the 2008 UEFA Champions League final, therefore helping Manchester United to the trophy.
Anderson spent 8 years at Old Trafford but the fact that he only has 105 league appearances to his name speaks volumes.
Simply put, the player never reached anywhere near his full potential. He performed effectively in small doses, coming into the side and looking great but the Brazilian never found the consistency levels needed to thrive on the top level.
He returned to his home country to play for Internacional but after featuring heavily for two seasons, was subsequently loaned out to Coritiba. Notably, Anderson has put on some weight and has often seemed disinterested in football. He's still amazingly only 29, but Anderson's chances to truly prove himself in European football seem long gone.