Michael Cheika says he has no fears about throwing young forwards into the fray against a physical Argentina pack after handing Lopeti Timani his run-on debut at Twickenham this Saturday - while Leroy Houston could yet play his maiden Test.
Timani was competing with the Bath-based Houston for the Wallabies No.8 spot and replaces the injured Sean McMahon, who is expected to miss a month with syndesmosis picked up in last weekend's loss to South Africa in Pretoria.
Houston could still earn a Test debut, having been picked on a nine-man bench with one to be omitted.
Experienced prop James Slipper has been dumped, with young props Allen Alaalatoa and Tom Robertson favoured - with the latter set to come on and play loosehead.
Should Cheika opt for a 6-2 bench, outside back Sefa Naivalu will drop off while if he chooses three backs then the final spot will be decided between Houston and fellow backrower Scott Fardy.
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The towering Rory Arnold has also been drafted in at lock, where he will partner fellow young gun Adam Coleman, at the expense of Rob Simmons in the only other change to the starting line-up from the 18-10 defeat.
Simmons passed all concussion protocols after suffering a head knock against the Springboks but was axed as Cheika searches for the best combination.
In opting for the relative inexperience of Timani (one Test) and Arnold (four Tests), Cheika said the Wallabies could have no fear in backing young stars.
"We can't be frightened to do that. No matter what game it is, whether it's Argentina (or anyone else)," he said.
Timani, who came off the bench in the victory over Argentina in Perth last month in his only Test to date, would bring some much-needed size and aggressive running at Twickenham on Saturday, Cheika said.
With the versatile Dean Mumm - a lineout specialist - making his home at No.6, Cheika believes the Wallabies need a hard-runner at the back of the scrum in the mould of veteran Wycliff Palu.
"I think with the profile of the other players we have, like the sixes who are more the jumping-type sixes, that ball-carrying, Wycliff Palu-style No.8 is something that we want to have as well," Cheika said.
"We want to be able to do both. Leroy is quite an abrasive runner as well, so there's a great opportunity to (see) how he'll go with the step up."
Arnold has impressed off the bench, and Cheika hopes he takes this weekend is a chance to prove he deserves to be a long-term starter.
WALLABIES TEAM TO FACE ARGENTINA
Israel Folau, Dane Haylett-Petty, Samu Kerevi, Bernard Foley, Reece Hodge Quade Cooper, Will Genia, Lopeti Timani, Michael Hooper, Dean Mumm, Adam Coleman, Rory Arnold, Sekope Kepu, Stephen Moore (capt), Scott Sio. Res: James Hanson, Tom Robertson, Allan Alaalatoa, Kane Douglas, Scott Fardy, Leroy Houston, Nick Phipps, Tevita Kuridrani, Sefa Naivalu (one to be omitted).
