Rocky Elsom has been relieved of the Australia captaincy for the World Cup in New Zealand.
The 28-year-old blindside flanker, who missed most of the Super 15 season because of injury, has been replaced by Queensland Reds captain James Horwill.
"It has become clear that the additional responsibility has been a distraction that Rocky doesn't need," said Wallabies coach Robbie Deans.
As expected, there was no place in the squad for utility back Matt Giteau.
The 28-year-old signalled his exclusion for the tournament, which starts on 9 September, via social networking site Twitter on Wednesday.
Back-rower Matt Hodgson has also been overlooked by Deans for the 30-man squad.
New captain Horwill is a 6ft 7in second row who led Queensland to their maiden Super Rugby title this season.
On the subject of Elsom, Deans added: "It is well documented that Rocky came into the Test season off a limited background in terms of preparation, having missed all but 60 minutes of Super Rugby due to injury.
"We all felt it was in the best interests, both of Rocky and of the team, to relieve him of the extra duties, with James's recent experience making him the best option to take over in the role.
"Rocky will remain a very important person within the group. He remains in the leadership group. When the proposal for the adjustments of the leadership was put to him, his immediate and impressive response was 'whatever's in the best interests of the team'."
Brumbies player Elsom said: "It's the way it goes. I mean, it's in the nature of the sport, you're always up for selection.
"We all want the same thing now so it's all heading towards that. I think it's important that everyone gets behind the captain, it can be a difficult job at times and you need everyone right behind you there."
Deans has picked six players who have recently suffered from injury, but said he was confident that Wycliff Palu, James Slipper, Tatafua Polotau-Nau, Rob Horne, Berrick Barnes and Drew Mitchell would all be fit for the tournament.
However, while squad members who are injured prior to, or during the tournament, can be replaced, all replacements are permanent.
"Looking at every scenario imaginable, and how that impacted on the squad, and our ability to still field a combination suited to the way we want to play, was a critical part of the selection process," said Deans.
Australia squad: B Alexander, A Ashley-Cooper, B Barnes, K Beale, L Burgess, Q Cooper, R Elsom, A Faingaa, S Faingaa, W Genia, S Higginbotham, R Horne, J Horwill (capt), D Ioane, S Kepu, S Ma'afu, P McCabe, B McCalman, D Mitchell, S Moore, J O'Connor, W Palu, N Phipps, D Pocock, T Polota Nau, R Samo, N Sharpe, J Slipper, D Vicerkman.