Australian coach Michael Cheika has included uncapped teenage center Jordan Petaia in his World Cup squad along with veteran David Pocock on Friday despite concerns over the loose forward's fitness ahead of the global showpiece in Japan.
Highly fancied Petaia is the only untested player in a seasoned squad captained by flanker Michael Hooper and boasting 1,406 caps of test experience, 200 more than the roster for the 2015 tournament.
Pocock has not featured in Wallabies gold since a test against Italy last November and he barely played Super Rugby this year while struggling with a problematic calf injury.
The 31-year-old will have only one warmup before the World Cup, a game against Samoa on Sept 7, to prove his body is still up to the rigors of test rugby.
Cheika also included veteran back Adam Ashley-Cooper for his fourth World Cup, just the second Wallaby to do so after George Gregan.
He has taken a gamble by only including two scrumhalves in Nic White and Will Genia, but has included three hookers in Tolu Latu, Folau Fainga'a and young Melbourne Rebel Jordan Uelese.
Uelese beats out experienced hooker Tatafu Polota-Nau, while lock Luke Jones, loose forwards Rob Valetini and Liam Wright and outside back Tom Banks also miss out after being named in the squad for the last two tests against New Zealand.
"We've become a really tight group and it was a very difficult process in picking only 31 players," Cheika said in a statement. "But I know each player selected will travel to Japan with the full support of those teammates who won't board the flight.
"These next few weeks are about building and adding that little extra edge as a squad and we'll be working hard to make sure we deliver on the qualities we want people to see when we run out on the field in Japan."
Australia take on Fiji in their World Cup opener in Sapporo on Sept 21 before their remaining Pool D matches against Wales, Uruguay and Georgia.
Forwards - Allan Alaalatoa, Rory Arnold, Adam Coleman, Jack Dempsey, Folau Fainga'a, Michael Hooper (captain), Sekope Kepu, Tolu Latu, Isi Naisarani, David Pocock, Izack Rodda, Rob Simmons, Lukhan Salakaia-Loto, Scott Sio, James Slipper, Taniela Tupou, Jordan Uelese
Backs - Adam Ashley-Cooper, Kurtley Beale, Bernard Foley, Will Genia, Dane Haylett-Petty, Reece Hodge, Samu Kerevi, Marika Koroibete, Tevita Kuridrani, Christian Leali'ifano, James O’Connor, Jordan Petaia, Matt Toomua, Nic White© (c) Copyright Thomson Reuters 2019. Click For Restrictions - https://agency.reuters.com/en/copyright.html