#4 Mauricio Pellegrino
Mauricio Pellegrino might be known now as the manager of La Liga side Leganes, or the former boss of Southampton. Liverpool fans might even recall him as the assistant manager to Rafa Benitez at Anfield. However, you'd be forgiven if you cannot recall the fact that Pellegrino has actually played for the Reds.
The former defender had been a part of Benitez's all-conquering Valencia side in the early 2000s and was brought to England by Benitez in January 2005. At 33 years old, Pellegrino reunited with his former manager. However, he was cup-tied for the Champions League and missed the Reds' iconic run to Istanbul.
The Spaniard did play 13 times for the Reds, as a back-up to the likes of first-choice central defenders Sami Hyypia and Jamie Carragher. Pellegrino would have frequent struggles due to the pace and the power of the Premier League, and left Liverpool at the end of his six-month contract for Alaves, where he ended up retiring.
He returned to Anfield in 2008 as Rafa's right-hand man and enjoyed a successful season before things started to go wrong at Anfield. He moved on to begin his managing career, coaching the likes of Valencia and Estudiantes. Mauricio Pellegrino is still finding his feet, currently at Leganes.