#4 Gerard Pique
Gerard Pique, the famous Spanish centre-back, came through the youth ranks of Barcelona and joined United as a teenager in 2004. However, he failed to cement his place in the starting line-up of United, who had Nemanja Vidic and Rio Ferdinand as their regular center-backs.
Yet, Pique managed to stay with the club till 2008, and also won one UEFA Champions League and one Premier League title with them. He played in 23 matches for United and scored 2 goals. Ultimately, he left the club in 2008 and subsequently joined Barcelona in 2009.
Pique evolved as a player while playing for Barca, and remained one of the best center-backs in the world for close to a decade. He is known for his distribution skills, clean tackling and ability to read the game. Pique has won 3 Champions League and 7 LaLiga titles with Barcelona. He has also scored 46 goals in 487 matches for them.