Aaron Mooy may miss at least the group stage of the Asian Cup after picking up a nasty knee injury in Huddersfield Town's clash with Arsenal.
The star midfielder is key to Australia's game, with Mooy's vision and touch able to pick out players and play them into space.
But he has reportedly picked ups suspected medial ligament injury at the weekend and could miss the next four to six weeks in rehab, according to The Australian.
The Asian Cup kicks off for Australia on January 6 when they play Jordan in United Arab Emirates which is likely to be too soon for Mooy to recover fully in time.
However he may be approaching match fitness in time for the knockout stages which begin on January 20.
The Socceroos are already missing teen flyer Daniel Arzani who has been ruled out for the season with an ACL injury on his senior Celtic debut.
And there are also doubts over fellow Celtic star Tom Rogic's fitness after he took a knock at the weekend too with speculation he may also face weeks on the sidelines.
Coach Graham Arnold is expected to name his squad for the tournament next week ahead of going into a camp around Christmas.
The Socceroos boss hadn't intended to name any extras outside of his core 23-man squad to avoid upsetting players' domestic clubs.
But the injury crisis may force his hand to have other options available to him if Mooy and perhaps Rogic don't recover in time to play a part.