Wallaby playmaker Matt Giteau looks set to be a controversial omission from Australia's World Cup squad in a bazaar fall from grace for the 92-Test backline ace.

The 28-year-old appears to have had a fallout with Wallaby coach Robbie Deans, who will announce his 30-man squad on Thursday.

Up until as late as last year Giteau was the highest-paid player in Australia and would have been expected to be a shoe-in for the World Cup.

However, the stalwart's failure to close-out several matches last years as the team's goal-kicker and an untimely dip in form may have come back to haunt him.

"Thank u ballboys, thank u linesman! That's it...", was Giteau's leading comment on Twitter on Wednesday.

Giteau's tweet indicates that Berrick Barnes is likely to have been preferred by Deans as Quade Cooper's understudy, having come through a series of concussion problems.

Barnes, together with several other high profile stars such as Drew Mitchell,  Tatafu Polota-Nau, James Slipper and Wycliff Palu must all come through fitness tests on Wednesday.

Deans admitted to AAP that he has already settle on a squad and doesn't expect any major surprises from the fitness testing.

"We've had all those internal selection discussions and we're clear in our mind," he said.

"We've been watching (the injured players) and we know where they're at but today is an opportunity to see them and talk to them.

"We've got the squad resolved, it's just communicating it now."