The Wallabies have suffered another blow with news that flyhalf Quade Cooper has been ruled out of the remainder of the Rugby Championship.

Scans in Brisbane on Tuesday revealed that Cooper has a small chip of articular cartilage in his right knee which will need to be attended to.

While the injury will require an operation to clean up and is to the same knee that was operated on after last year’s World Cup, it is not a long term injury and so may not rule Cooper out of the Wallabies' year-end tour in November.

A decision on the flyhalf's availability for that trip will be made once his rehabilitation is underway.

The loss of the mercurial playmaker is the latest in a series of injury blows for the Wallabies which has seen senior players such as James Horwill, David Pocock and Will Genia sidelined already.

Cooper had a somewhat indifferent performance against Argentina last week, but he is a relatively experienced player and helped Australia to the Tri-Nations title last year so his absence will be felt.

The versatile Berrick Barnes, who started at fullback against the Pumas, is the most likely candidate to take his place at flyhalf for the Wallabies two remaining Tests in the competition.

The 28-man Wallabies squad for the away leg of the Rugby Championship, which features Tests in South Africa and Argentina, will be named on Wednesday.