Sydney FC believe they have enough depth to cover the sudden departure of Seb Ryall but the players are shocked the stalwart decided to quit football during the middle of the season.

The club's third most capped player announced his exit from professional football on Wednesday to pursue a life away from the game. A move that stunned several members of the Sky Blues' squad.

Time out: Seb Ryall has decided to quit professional football Credit:Ben Rushton

It's understood Ryall turned down the opportunity to play for rival A-League clubs as he didn't want to play against Sydney FC - the club he made 168 A-League appearances for - and was not interested in playing in South East Asia.

His departure leaves Sydney FC with only three central defenders ahead of a busy end to the season. The club will have to balance the A-League with their Asian Champions League campaign.