The Wallabies will be without three players for their clash with Argentina after being hit by injuries in their victory over South Africa last weekend.
Matt Giteau has been the latest player to be ruled out of this week's Rugby Championship Test in Argentina with a sternum injury picked up against the Springboks.
The news follows the loss of Will Genia and Rob Horne to injuries, with the Wallabies forced to call in reinforcements for their trip to South America.
Chest scans cleared Toulon-based Giteau of any serious damage after Saturday's game against the Springboks but team officials said they have opted to rest the 32-year-old for the next stage of the tournament.
"I know how desperate Matthew was to play and continue to contribute to this group over the next week, his leadership and presence off the field will be missed," Wallabies coach Michael Cheika said.