Brisbane - Will Genia and Rob Horne were on Sunday ruled out of Australia's next Rugby Championship Test in Argentina with injuries following the last-gasp win over South Africa.
Scrumhalf Genia will have knee surgery after he was replaced at half-time in Saturday's 24-20 win over the Springboks in Brisbane.
Centre Tevita Kuridrani scored with the last play of the match to give Australia a dramatic win over the Springboks.
Winger Horne has a calf muscle strain and will miss the trip to Argentina where the Wallabies will play the Pumas in Mendoza on Saturday, July 25.
Wing Nick Cummins and scrumhalf Nic White will join the squad as their replacements, with two further additions in hooker James Hanson and prop Tetera Faulkner.
"It's disappointing for Will and Rob to miss this upcoming Test," Wallabies coach Michael Cheika said.
"They have both made an outstanding contribution to the group these past two weeks, and will continue to remain part of the wider squad from afar.
"Will is due to have some minor surgery this week and we are confident he will be available for selection for the Bledisloe Cup series.
"We have taken a conservative approach with Rob and the additional week off will serve him well going into the next stage of our campaign."
The Wallabies squad for Argentina:
Adam Ashley-Cooper, Kurtley Beale, Quade Cooper, Nick Cummins, Tetera Faulkner, Scott Fardy, Israel Folau, Bernard Foley, Matt Giteau, James Hanson, Scott Higginbotham, Greg Holmes, Michael Hooper, James Horwill, Sekope Kepu, Tevita Kuridrani, Stephen Moore (captain), Drew Mitchell, Ben McCalman, Sean McMahon, Dean Mumm, Nick Phipps, David Pocock, Tatafu Polota-Nau, Scott Sio, Rob Simmons, Will Skelton, James Slipper, Matt Toomua, Joe Tomane, Nic White