Sydney FC goalkeeper Danny Vukovic in talks with Racing Genk

Sydney FC goalkeeper have released Danny Vukovic, who is on the verge of securing a move to Europe with top-flight Belgian outfit KRC Genk.

The A-League's gloveman of the year is set to sign with the former club of Socceroos teammate Mat Ryan, in a leap that will significantly elevate his hopes of playing for Australia in a World Cup year.

The opportunity is fitting reward for a career-best domestic season.

"I'm very sad to leave but, to have such an unbelievable opportunity so late in my career, is something that I just couldn't turn down," Vukovic said on Wednesday via a Sydney statement.

"It's something I could not have foreseen and I would like to thank Sydney FC, the board of directors and [coach] Graham Arnold for their kindness, understanding and support in allowing me to make this move.

"I'm very proud at what we have achieved ... and very fortunate to have had the best season of my career since joining Sydney FC.

"It has been an amazing 12 months for me and my family -- a year I will always remember."

Socceroos first choice Ryan spent the back end of last season at Genk on loan from Valencia before signing with English Premier League new boys Brighton.

The uncapped Vukovic is in Russia with Ryan and the national team at the Confederations Cup. He has another year on his contract but is poised to move with his family to Belgium on the assumption Genk have matched Sydney's desired transfer fee believed to be up to $1 million.

The 32-year-old's departure is a blow to Sydney's title defence and leaves the club without the stopper. Vukovic notched an A-League record-low 16 clean sheets and shipped just 13 goals all season.

"Danny was superb last season and it's no secret how highly I regard him as a player and as a person," Arnold said.

"No one at Sydney FC wants Danny to go and we are naturally devastated to lose him ...

"It's the kind of challenge faced by Australian clubs and we cannot stand in his way."

Vukovic holds the record for most A-League appearances (278) across Central Coast, Wellington, Perth and Melbourne Victory before finally winning his first championship last season with Sydney.

The veteran spent an ill-fated two months in Turkey with Konyaspor in 2010 along with a five-month loan stint at Japanese top-flight side Vegalta Sendai in 2014, but made no appearances for either.

His spectacular return to form coincided with a move home to Sydney for better family and medical support for his son Harley, who recently had a life-saving liver transplant.

The switch from Victory also reunited him with his first goalkeeper coach John Crawley, who helped rebuild his confidence before a Socceroos recall.