3. Mikael Silvestre:
Silvestre was a French left-back, who could also play as a centre-back. He was signed by Ferguson for United in 1999 and played for them till 2008. Silvestre had to fight with the likes of Gabriel Heinze and Patrice Evra for a place in the starting line-up and sometimes warmed their bench. Still his exceptional abilities in the air and good positional sense earned him 361 appearances for United in 9 seasons. He also won 4 league titles, 1 UEFA Champions League title and 1 FA Cup with them.
He left United for Arsenal in 2008 and spent a couple of seasons with the London club. He played both as the left-back and centre-back for Arsenal as well and got some starts for them as they were seeking a replacement for Ashley Cole, who had left for Chelsea. However, the advent of William Gallas and Gael Clichy meant that Silvestre again became unsure of a place in the starting line-up. He managed to play 43 matches for Arsenal and score 3 goals.