The midfielder's hopes of being a part of Australia's Asian Cup defence appear in doubt after Mooy posted an image of him sitting on a treatment table in Huddersfield Town's dressing room with his right leg in a brace.

The image comes with three thumbs down emojis on it but no words or explanation from Mooy.

It's been reported the 28-year-old suffered a medial ligament strain in the Terriers' 1-0 loss to Arsenal on the weekend.

Socceroos medical staff were unaware of the extent of any injury on Tuesday and were awaiting an update from Huddersfield.

If the injury is as bad as reported Mooy would almost certainly miss Australia's group stage matches against Jordan, Palestine and Syria at the tournament in the UAE next month.

A four-to-six week layoff could still leave Mooy able to play the latter stages of the tournament if coach Graham Arnold chooses to select him when he names his 23-man squad next week.

Mooy's injury may open the door for Melbourne Victory midfielder James Troisi.

The 2015 Asian Cup hero hasn't featured for the Socceroos after missing out on this year's World Cup squad.

But Troisi's form for the Victory in the A-League could force him back into the setup, particularly given his big-game experience for the national team.

Another potential name who could benefit should Mooy be ruled out is Troisi's Victory teammate Terry Antonis, who has been a large part of the team's five straight A-League wins.

Fellow midfielder Tom Rogic is also reportedly struggling with a knee injury, but while Socceroos staff are awaiting an update from his Scottish club Celtic they are confident he's in no danger of missing the Asian Cup.

Australia begin their title defence against Jordan in Al Ain on January 6.

Australian Associated Press