Almost 20 per cent of Australia's eventual Rugby World Cup (RWC) squad might play just one, or even none, of the five Tests leading up to the tournament due to injury.

Wallabies' coach Robbie Deans says prop James Slipper, hooker Tatafu Polota-Nau, No.8 Wycliff Palu and halfback Luke Burgess are all out for six to eight weeks, while winger Drew Mitchell is already battling to be fit for the tournament starting in September.

Australia's international campaign starts against Samoa in Sydney on July 17 and selectors will announce a 40-man squad six days earlier.

"The likelihood is we will name blokes who aren't able to play in the first instance, but who we will want to get under way, given that we have such a short preparation window," Deans told reporters on Friday.

The Wallabies play four Tri-Nations Tests, the last against New Zealand in Brisbane on August 27, just two weeks before Australia's first RWC game against Italy in Auckland.

Deans admits a distinct possibility there will be some players chosen in the RWC squad on August 18 who will have missed all five lead-up Tests.

"We've got a number of blokes who won't be available for the front end of Tri-Nations, who probably at best will be available for the last fixture," Deans said.

"There's likely to be some that we'll have to make a call on, but it will be having observed their training, there's not a lot of risk in that now.

"You can't hide in terms of the conditioning work that you do. We won't be picking anyone who hasn't shown that they are close and ready to go, because it's such a short campaign, you just can't afford to."

He said captain and blindside flanker Rocky Elsom has resumed running and is on track to play against Samoa.

Inside back Berrick Barnes, who stood down from the latter stages of the Waratahs' Super campaign after suffering head knocks, will set his own time to resume playing.

With Burgess and Polota-Nau sidelined, Deans hinted there could be uncapped players trialled at hooker and halfback in the coming Tests.

Rising Melbourne star Nick Phipps is a contender for a halfback spot, while Deans nominated Force duo Nathan Charles and Ben Whittaker, Queensland's James Hanson and Waratah John Ulugia as potential hookers.

Deans said tighthead prop, hooker and second row are the positions generating most discussion among selectors, but he has no worries about the depth of talent.

"The good thing is we've got choice in each position. It's not that we're looking under stones," Deans said.

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