Wallabies coach Michael Cheika says he's not afraid to keep the revolving door going after making the surprise decision to drop lock Kane Douglas for Saturday night's clash with Argentina in Perth.
Douglas was axed in favour of veteran Rob Simmons, who'll partner emerging star Adam Coleman in the sixth different lock combination used by Cheika this year.
Cheika wasn't afraid to make some other big calls.
Veteran winger Drew Mitchell was dumped from the squad altogether, with Cheika concerned about the 32 year-old's speed.
And medical student Tom Robertson will make his debut off the bench in place of injured prop Allan Alaalatoa (knee).
Cheika said second rower Lopeti Timani, who was named on an extended bench, would also make his debut.
Australia's line-out was a big issue during the side's recent six-match losing run.
There were signs of improvement in last week's 23-17 win over South Africa in Brisbane, however it wasn't enough to convince Cheika to stick with Douglas, who is still finding his feet after returning from a knee reconstruction less than three months ago.
"He's been a very good player for Australia over many years - and he just needs to find that groove," Cheika said.
Simmons was recalled following two solid performances in the NRC.
But it was his hot training form that convinced Cheika the 63-Test veteran was ready for another shot.
"There's a bit of a challenge now coming from the younger brigade of players who are coming through, and it's up to everyone to compete for their spot and improve their game," Cheika said.
"It's not like Kane was playing terribly. We are trying to get ourselves to a better standard."
Cheika said he wouldn't be afraid to keep the revolving door going if his players didn't perform.
"Everyone's always crying about us having no depth," Cheika said. P
"Well, we're taking the measures to create depth at the best level.
"It doesn't always work out. Sometimes it works out fantastically."
Mitchell returned from injury off the bench in last week's win over South Africa, but he has been replaced in the extended squad by Henry Speight.
Simmons has fond memories of playing Argentina, having scored an intercept try after just 68 seconds of Australia's 29-15 World Cup semi-final win last year.P
Argentina made four changes to the side that lost 57-22 to the All Blacks last week.
Brumbies scrumhalf Tomas Cubelli earns his first start since last year's World Cup, while Juan Manuel Leguizamon returns at blindside flanker after recovering from a leg injury.
Santiago Gonzalez Iglesias replaces injured centre Juan Martin Hernandez, while Javier Ortega Desio moves to lock to fill the void left by the injured Guido Petti.
Wallabies: Israel Folau, Dane Haylett-Petty, Samu Kerevi, Bernard Foley, Reece Hodge, Quade Cooper, Will Genia, David Pocock, Michael Hooper, Dean Mumm, Adam Coleman, Rob Simmons, Sekope Kepu, Stephen Moore, Scott Sio. Res: Tatafu Polota-Nau, James Slipper, Tom Robertson, Rory Arnold, Lopeti Timani, Sean McMahon, Nick Phipps, Tevita Kuridrani, Henry Speight (one to be omitted)
Argentina: Joaquin Tuculet, Santiago Cordero, Matias Moroni, Santiago Gonzalez Iglesias, Lucas Gonzalez Amorosino, Nicolas Sanchez, Tomas Cubelli, Facundo Isa, Juan Manuel Leguizamon, Pablo Matera, Matias Alemanno, Javier Ortega Desio, Ramiro Herrera, Agustin Creevy, Nahuel Tetaz Chaparro. Res: Julian Montoya, Lucas Noguera, Enrique Pieretto, Marcos Kremer, Leonardo Senatore, Martin Landajo, Gabriel Ascarate, Matias Orlando.
