Playmaker Tom Rogic is also a concern but is expected to be available, both struggling with knee injuries at the worst possible time for coach Graham Arnold as he ponders his squad for January’s defense of the trophy in the United Arab Emirates.
Mooy suffered a medial ligament injury playing for Huddersfield against Arsenal at the weekend, but the Socceroos medical staff have yet to learn the full extent of the damage as they liaise with their Terriers counterparts.
The fact that the 28-year-old, who is enjoying a purple patch of form, finished the game has provided hope that it may only be a partial tear, which would likely sideline him for around four weeks.
A full tear - which scans may yet reveal - would require a six-week lay-off, or more, and likely rule him out for the entire tournament.
Australia face Jordan on January 6, Palestine (January 11) and Syria four days later. The round of 16 kicks off on January 20.
It’s understood that Socceroos physio Phil Coles could be sent to the UK to monitor and assess the situation - in collaboration with Huddersfield’s medical staff - if it’s deemed necessary.
Rogic’s situation is less serious as Celtic and the Socceroos manage an on-going knee issue which required him to be rested from Arnold’s third game in charge - last month’s 3-0 win over Lebanon.
Rogic played until the 67th minute of Celtic’s 5-1 win over Kilmarnock at the weekend as they went top of the Scottish Premiership.
And the Socceroos hierarchy are hopeful that, unless his problem worsens, he should still be available for selection next month.
Both players have been pivotal for their clubs this season; Mooy making 15 Premier League appearances and scoring twice for relegation-battling Huddersfield, whilst Rogic has made 21 appearances in all competitions for Celtic, with three goals.
