Adrian Segečić had reportedly threatened the change of allegiance last year as frustrations grew over his lack of progression into the Socceroos setup, with head coach Tony Popovic selecting him in a wider squad for last year's two-legged series against New Zealand but not handing him a first team debut.
Segečić had made 19 appearances for three Australia underage sides between 2019 and 2024, including the 2023 AFC U-20 Asian Cup, but was unable to make it any further into the national team despite a breakout 13-goal season for Sydney FC (2024/25) that ultimately prompted his move to Championship club Portsmouth.
The 21-year-old immediately won Pompey fans over by scoring in each of his first two Championship appearances but, despite scoring a further four league goals, has fallen out of John Mousinho's starting lineup in favour of Englishman Conor Chaplin.
With no fanfare or announcement, FIFA's Change of Association Platform revealed on Friday night that Segečić had formally cut ties with the Socceroos.