Australia's Asian Cup defence has taken a hit with star midfielder Aaron Mooy officially ruled out of the tournament.
The Socceroos confirmed on Monday a knee injury would sideline the 28-year-old for the entire tournament, which kicks off in the UAE on January 6.
Mooy suffered the injury playing for Premier League club Huddersfield Town against Arsenal earlier this month.
Socceroos physiotherapist Phil Coles travelled to England for an independent assessment of the injury after Huddersfield initially ruled Mooy out for eight weeks.
Socceroos coach Graham Arnold said it was unlikely Mooy would be fit before the quarter-finals and the decision was made to omit him from his 23-man squad.
"In making the assessment on the injury we agreed Aaron would need at least another month to return to fitness," Arnold said.
"In a best-case scenario, this would mean he would not be ready to play until after the quarter-final stage.
"With so many games in such a short period we felt it would be best to bring in a player that is fully fit and ready to go from the outset."
Austria-based James Jeggo will replace Mooy.
Jeggo debuted for the Socceroos in last month's friendly against Lebanon in Sydney.
"Initially James was very unlucky to miss out on the squad, but sometimes these things happen in football and we are glad we can provide him with this opportunity," Arnold said.
Mooy joins Celtic winger Daniel Arzani (knee) on the sidelines as the Socceroos attempt to defend the title won on home soil in 2015.
In better news for Arnold, Mathew Leckie will join the Socceroos camp in the UAE in the coming days despite injuring a hamstring in a Bundesliga match for Hertha Berlin on the weekend.
Leckie will be assessed upon his arrival in the UAE but an initial assessment suggests he will be fit to take part in the tournament.
The Socceroos begin their campaign against Jordan in Al Ain on January 6.