Now 20, the diminutive De Silva attracted blanket coverage when he signed for Italian giant AS Roma back in 2015.
But that reputed $1.5 million move from Perth Glory quickly morphed into a loan to Eredivisie side JC Roda, whom he left in January having made just 16 appearances across two seasons.
The former Young Socceroo was even called up for the senior squad by Ange Postecoglou for a FIFA World Cup qualifier against Kyrgyzstan in 2015, in recognition of his potential.
But De Silva's stocks took a tumble on departing the Netherlands and he has spent the past six months on an intense strengthening program aimed at battle-hardening his slight frame for a long-term future at the top level.
Mariners CEO Shaun Mielekamp revealed that coach Paul Okon, whose relationship with De Silva stretches back to their time together with the Australia's under-20s, has been in talks with gifted youngster since January, and even tried to sign him then.
Mielekamp is confident that, after a six-month wait, a deal is almost done now.
"It's looking positive but until they sign on the dotted line you can never say for sure," he explained.
"If it all goes through Daniel will be an important recruit for us.
"He and Paulo are close (from the under-20s) and have been talking for some time.
"We hoped it would happen in January but couldn't get it over the line back then."
De Silva, by his own admission, was at times exposed for being a tad lightweight in the Netherlands.
But, with the benefit of a strength and conditioning program behind him, he now has the chance to rebuild for the 2017-2018 A-League season, and potentially another shot at Europe beyond that.
De Silva is rated by former Socceroos enforcer Vince Grella, now his agent, as one of the brightest Australian products of his generation.
And, despite hitting a speed hump this year, a move to Gosford to work with a coach with whom he has a chemistry, offers a tantalizing chance to regain lost momentum.
His signing represents an act of faith by Mariners management as the club's recent recruitment drive gathers steam.
Okon has already brought in Dutch midfielder Tom Hiariej from Groningen to cover for the retirement of Nick Montgomery, former Sydney FC and Newcastle Jets wide player Andrew Hoole and ex-Melbourne Victory defender Alan Baro as the Mariners serve a notice of intent for next season.
They're also looking to recruit a first choice keeper following the exit of Paul Izzo to hometown team Adelaide United and at least one more striker.
"We are very confident next season will be a good one for us," added Mielekamp.
"There's a feeling about the place that there's a new era at the club and we're heading in the right direction.
"It's an exciting time ahead that's for sure."
While the cash-strapped Mariners won't be digging as deep as some, Mielekamp insisted that wise recruitment could be the key to staying competitive.
"It's about being smart – it doesn't matter how much money you've got ... if you spend poorly you're in trouble.
"The situation at the club is that we are more stable than we have been in the past and we are in a position to move forward."