Jason Gillespie and Stuart MacGill are in doubt for the second Test against Zimbabawe, starting on Friday. The Australians were injured on day three of the first Test and took no further part.
Scans revealed Gillespie suffered a tear in a left-side back muscle, while MacGill has a tear in his right calf.
"Given the injuries and the amount of time between Tests, I guess that puts a cloud over their availability for Sydney," said team physio Errol Alcott.
"Both have fresh injuries, so we will monitor their progress closely over the next 24 hours before coming to any conclusions.
"With Jason Gillespie, he felt a degree of discomfort early in yesterday's second innings.
"He wanted to keep bowling, but scans have revealed that his grunt muscle is strained, so in the interests of his longer term future, we need to hold him back."
It is the latest in a long line of setbacks for the injury-prone Gillespie.
After missing 38 of the following 79 Tests after his debut in 1996, the paceman managed to shrug off his various injury woes and become more of a permanent fixture in the Australia team.
But disaster struck during the World Cup this year when a tendon injury forced him out of the tournament after the group stage.
"I understand the need to take a cautious approach to this injury because it has set me back in the past," Gillespie said.
"I will do whatever it takes to get things right prior to the second Test, and I guess we will have a better idea as to how the injury is going over the day or so."
Of leg-spinner MacGill's injury, Alcott said: "Stuart experienced sharp pain during the course of play.
"The calf is torn, which is a genuine concern considering it is his set-up and landing leg.
"We will treat him and assess his progress over the course of the next 24 hours."
Australia are set to name their squad for the second Test at the conclusion of the Waca match.
MMIX
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It's another blow really at a time when I felt the ball was coming out nicely 
