Sydney FC have secured the signature of Spanish defender Diego Caballo on a two-year deal.

Steve Corica has kicked off an overseas signing spree for Sydney FC by confirming the capture of Spanish leftback Diego Caballo on a two-year deal.

The 28-year-old joins from Alabacete after having stints with Deportivo La Coruna and Extremadura and will fill the void left by Joel King, who moved to Danish side OB midway through last year's A-League Men season.

Caballo, who spent time at Real Madrid and Valencia but failed to make a first-team appearance, takes up one of Sydney's visa spots.

The club is well-placed to make a splash in the market after the exits of Luciano Narsingh, Kosta Barbarouses, Bobo and new Western Sydney Wanderers recruit Milos Ninkovic following a season where they missed the play-offs.

Corica said Sydney would look to add two attacking players and a centre-back alongside Caballo and the club's other visa player Adam Le Fondre prior to the season starting in October.

"Diego will give us great strength in depth on our left-hand side," Corica said.

"He's a player who likes to get forward and gets crosses into the box so he will be a good attacking player for us.

"He is also quick and strong and with an attacking mindset and will be exciting for the fans.

"He has also kept himself in good physical condition since the end of the season in Spain so he will be able to hit the ground running."