Center back who joined Newcastle United in 2008 after spending four years with Deportivo La Coruna.
A strong career with his hometown Boca Juniors team earned him the attention of AC Milan.
He spent five seasons with AC Milan but was sent on loan to four different teams during his time with the club.
He grew up in Cordoba, Argentina.
He was joined by Lionel Messi on Argentina's national team in 2005.