Sydney FC's championship defence has already been hit by the loss of its first choice goalkeeper, Danny Vukovic, who has moved to Belgian club Genk. 

And now its Premiership winning coach Graham Arnold's biggest off season task will be keeping the rest of his squad together, as suitors, both local and from overseas, circle around some of his title winning stars.

Midfielder Josh Brillante is the target of some inquiries, as are defenders Rhyan Grant  - who was called into the Socceroo squad earlier this year - and Michael Zullo, once a first choice international when Holger Osieck was Socceroo coach.

The Sydney boss has brought in Paulo Retre to provide back up in midfield and the 24-year-old could turn out to be a shrewd investment as he is capable of operating as a full back as well as in the centre of the park.

Retre's departure from City - he signed for champions Sydney earlier this month - breaks the chain linking City to its predecessor, Melbourne Heart.

Retre, whose chances of playing in the City first team this season were likely to be limited, was the last remaining player who was at the club when Manchester City bought it in 2014. He had joined Heart from Melbourne Victory, where his career began, in 2012.

Meanwhile Melbourne City's new coach, Warren Joyce, will largely have to work with the players already at the club as he prepares for his first season in charge in the A-League.

But the former Manchester United coach does have a handful of senior places still to fill, including two foreign visa slots up his sleeve with the departure of Nicolas Colazo and Thomas Sorensen.

The Latrobe based club will probably be one of the few that enjoys relative continuity from A League season to season as most of its required players were locked away on deals for the 2017-18 campaign.