Sarmiento spent most of his career in Argentina with
Talleres de Córdoba,
Olimpo and
Argentinos Juniors. He had a brief spell on loan to Bulgarian team
Litex Lovech and he spent the early part of the 2006–07 season on loan at English club
Southampton. Sarmiento arrived at Southampton as a holding midfielder to organize the midfield but on 19 January 2007 he was released, having only made four appearances for the club, three in the
Football League Cup and one in the
FA Cup. Sarmiento re-joined his previous club Argentinos Juniors on loan until June 2007 before joining
AEL in Greece on a free transfer on a two-year contract plus one-year extension option. For the next two seasons, Sarmiento was a fundamental part of Larissa's squad, playing more than 60 games in total with the
maroons, and being one of the key players in midfield. In summer 2009, he transferred to
Atromitos, rejoining his old Larissa coach
Georgios Donis. After a two-year stint at Atromitos, he left Greece to join the newly promoted
Argentine Primera División side
Unión in July 2011. ==References==