Gun defender Alessandro Circati has suffered an ankle injury, joining a mounting list of Socceroos under an injury cloud ahead of upcoming friendlies against Venezuela and Colombia.
Circati was forced off the field 41 minutes into Parma's 3-1 Serie A loss to Bologna on Sunday.
He looks set to join fellow defenders Harry Souttar, Jordy Bos, Aziz Behich and Jacob Italiano on the sidelines.
Australia will face Venezuela on November 15 (AEDT) in Houston, Texas then Colombia in Queens, New York on November 19 (AEDT) - two of the host cities for next year's World Cup finals.
Central defender Circati had slid in to make a tackle on Tommaso Pobega and snuffed out the Bologna attack, but his right ankle wobbled and flexed awkwardly when he made contact.
Circati, 22, stayed down, and immediately grabbed at his right ankle in pain before receiving treatment.
He limped off the field with assistance before being substituted.
Reports out of Italy said Circati had a sprained ankle, but the Socceroos will clearly sweat on an update on their talented centre-back.
Regardless, if there is any doubt over Circati, who has twice captained the Socceroos but is only 13 months on from an ACL tear, it seems unlikely coach Tony Popovic would risk him.
Emerging star Bos is expected to be sidelined for several weeks with a hamstring injury suffered at Feyenoord - a recurrence of an injury he had last year.
Fellow full-back Italiano (calf) and veteran Behich (hamstring) have also suffered soft-tissue injuries, while Ryan Strain missed Dundee's latest game with hamstring tightness.
Behich, who was a late withdrawal from Melbourne City's draw with Brisbane on Friday, didn't travel to Japan for Asian Champions League Elite duties and is in doubt for Saturday's derby against Melbourne Victory.
He would appear touch-and-go to be included in Popovic's squad, set to be named later this week.
If Behich is out, it means neither recognised left-back is available, with left-sided centre-back Kye Rowles the most well-credentialed fill-in.
Souttar is still on the comeback trail from the achilles tear he suffered last December.
Veteran Mathew Leckie, who has been playing as a defensive midfielder at Melbourne City, is also injured.
Yet to play under Popovic due to recurring soft-tissue injuries, Leckie strained his hamstring on Friday.
Jackson Irvine and Riley McGree should both be in the frame after returning from foot injuries at club level for FC St. Pauli and Middlesborough respectively.
Young striker Mohamed Toure will head into camp in red-hot form after scoring two goals for Randers overnight.
