First-choice striker Tomi Juric has been ruled out of the Socceroos' AFC World Cup qualifier against Thailand after scans confirmed the extent of his knee injury.
He'll be replaced by China-based standby Apo Giannou, who's on his way to Bangkok for the Nov. 15 clash.
Juric limped off the field eight minutes into his match for Swiss outfit FC Luzern on Sunday with suspected ligament damage.
"We have had confirmation from the medical staff at Luzern that Tomi has suffered a knee injury that will rule him out of the match against Thailand," Australia coach Ange Postecoglou said in a statement.
"Over the last 18 months we have worked hard to ensure we have depth and we have full faith in Apo to join the squad and get the job done."
The news is another injury blow for Australia after foot problems ruled out midfielder Massimo Luongo and back-up goalkeeper Mitch Langerak for the game in Bangkok, which marks the halfway point of the Socceroos' final stage on the road to Russia 2018.
Luke Brattan has been called up to replace Luongo after he was cut from Postecoglou's extended 30-man squad last week, while Swansea City gloveman Mark Birighitti steps in for Langerak.
Second from six teams in Group B and between leaders Saudi Arabia and Japan, Australia need three points against last-placed Thailand to stay in the hunt for automatic qualification as one of the top two sides.