The 21-year-old joined the Mariners in a controversial deal last year which saw him sign a marquee contract with the Central Coast side – but with the majority of his salary covered by Serie A side Roma.

They agreed to pick up around 200,000 Euros of his contract each year in return for an option to sign him for free at each Italian transfer window.

The deal attracted scrutiny from the FFA and others as a possible third party ownership deal, but the four year contract was carefully worded to avoid falling foul of FIFA laws, including extending it from the previously announced three year deal to four years to further protect the club.

The latest window for De Silva to join Roma closed on June 30 without Roma exercising their option... but the Mariners are now believed to be under intense pressure to release De Silva for free to join Sydney.

De Silva is said to have refused to train with the club since pre-season training began at the start of last month.

It follows on from the player ruling himself out of the F3 derby match against Newcastle Jets in April (which saw the Gosford outfit smashed 8-2), effectively cutting his ties with the Mariners from that point on.

But the Mariners are refusing to release the player under a mutual termination agreement to join another A-League side.

FFA regulations prohibit any transfer fees between A-League clubs, but the Mariners are unwilling to let de Silva go for free when he still has three years left on his deal.

It is understood Roma have also been applying pressure on the club to rip up De Silva's contract, despite the player never having been on Roma's books.

De Silva was announced as signing for Roma in 2014 but the deal apparently fell through because of a shortage of overseas signings slots in their squad.

Instead he joined Roda in Holland on loan from Perth Glory before later joining the Mariners after an injury-beleaguered stint in Europe.

The club and player are now at a stalemate, with the Mariners publicly insisting De Silva is simply on extended annual leave and looking forward to his return.

But in reality, they are understood to have now stopped his pay and are looking for help from the FFA and PFA to resolve the situation.

De Silva's representatives are said to want him to move from the club following the exit of former coach Paul Okon and now want him to work with Steve Corica at Sydney.

An alternative move to Melbourne City fell through because of De Silva's marquee wage demands and a lack of marquee slots at the club.

But De Silva – who is represented by former Socceroo Vince Grella – could possibly find a home at Sydney if their marquee star Bobo moves on.

However the Mariners now hope, if De Silva refuses to rejoin the squad, that he will be signed by an overseas club for a transfer fee rather than be allowed to leave to join a rival for free.

A club spokesman added: "Daniel's been on extended annual leave and we're looking forward to him coming back to training."