Wallabies coach Michael Cheika has bulked up his bench with back row reinforcements, dropping a second-row selection bombshell in the process.
Ben McCalman and Dean Mumm will be on the pine as potential back row replacements, also giving the Wallabies more line-out options coming off the bench.
Cheika has changed his bench balance to a five-three split for the second Test, after a more forward-heavy split in the first Test in Brisbane.
Liam Gill, James Horwill and Wycliff Palu were the three players omitted from the extended bench that Cheika named earlier this week.
The big surprise, though, was Cheika declaring last week's starter Rob Simmons, the Wallabies line-out caller for the World Cup, had been dropped rather than ruled out with a back injury.
"He was available for selection this week," Cheika told the Australian Rugby Union's official website.
The move is somewhat of a shock, with Cheika bringing Brumbies duo Sam Carter and Rory Arnold together and Cheika said it would give Simmons a chance to respond to the challenge.
"Any player that's left out is unhappy obviously so that's the challenge for him to improve and get his spot back like all players who are left out of a team," he said.
"That's the nature of rugby it has been forever. Some guys get picked some guys don't and it's how you react accordingly.
"That's what we're looking for from the players who have been brought into the team is here's an opportunity for the players who have remained in the team, here's another opportunity to go and do your best, put your best foot forward.
"You've only got a limited amount of opportunities in the Test jersey so you've got to take every one. Here's a chance for a guy who's been knocking on the door in that role in Sam Carter and going to be his opportunity to be taken."
Cheika said there was never any sure things when it came to team selection.
"I've never heard of the phrase 'selection guarantee'," he added.
"The minute someone's guaranteed so it feels like he's guaranteed selection he's never going to perform. Sure you don't want him stressing about things or whatever but you've got to know that.
"This is the national team and there's a lot of players that are vying for the one jersey and that's the way it should be."
The new second row combination will be familiar to captain and Brumbies hooker Stephen Moore, but Moore believes Saturday night would be the true test of the combination.
"I guess you know them pretty well but it's a different scenario," he said.
"We've worked on that part of the game as we do every week. You work with the hope that when you go out there under pressure that's what you practise for so we're going to get that tomorrow night."
Cheika said the combination of Ben McCalman and Dean Mumm coming off the bench would give the side the versatility it needed, along with that 5-3 split.
Australia (revised): 15 Israel Folau, 14 Dane Haylett-Petty, 13 Tevita Kuridrani, 12 Samu Kerevi, 11 Rob Horne, 10 Bernard Foley, 9 Nick Phipps, 8 Sean McMahon, 7 Michael Hooper, 6 Scott Fardy, 5 Sam Carter, 4 Rory Arnold, 3 Sekope Kepu, 2 Stephen Moore (c), 1 James Slipper
Replacements: 16 Tatafu Polota-Nau, 17 Toby Smith, 18 Greg Holmes, 19 Dean Mumm, 20 Ben McCalman, 21 Nick Frisby, 22 Christian Leali'ifano, 23 Luke Morahan
Date: Saturday, June 18
Venue: AAMI Park, Melbourne
Kick-off: 20:00 local (10:00 GMT)
Referee: Craig Joubert (South Africa)
Assistant Referees: Nigel Owens (Wales), Mike Fraser (New Zealand)
TMO: Glenn Newman (New Zealand)