Duke - a revelation for Western Sydney Wanderers since his January return to the A-League after four years in Japan - went down awkwardly against Gold Coast Knights on Thursday night.
An MRI scan on Saturday will reveal the extent of the damage.
There are initial concerns that Duke, 28, may have suffered a repeat of the ACL injury he sustained playing for Shimizu S-Pulse back in April 2016.
He went over on the same leg and both he and Wanderers coach Markus Babbel are praying the fears of a second hammer blow prove unfounded.
Back in favour with the national team after a long absence, Duke was impressive for the Socceroos in June’s 1-0 loss against Korea Republic and was shaping as a strong contender for future call ups from Graham Arnold on the long and winding qualification campaign for the 2022 FIFA World Cup in Qatar.
If the scans confirm the club’s worst fears, Duke could be sidelined for up to 10 months - meaning he would miss the entire season.
With four goals from 11 appearances so far under Babbel, Duke was a breath of fresh air at the club and was shaping as one of Wanderers’ poster boys for the 2019-2020 campaign.
His ability to operate anywhere in the front third and hurt defenses with his pace and penetration has been a boon for Babbel, who will be left with a huge hole to fill if he’s rubbed out for the year.
Duke was aiming to use the new season as a springboard back to an overseas club, telling The World Game last month: “The itch is certainly still there.
“I want to go back and make a bigger impression and a bigger name for myself.
“That could be in Asia again - I’m certainly open to going back to Japan - or even Europe still.”
