Wallabies pivot Quade Cooper needs more surgery on the same knee he injured at last year's World Cup and has been ruled out of the rest of the Rugby Championship.
The Australian Rugby Union (ARU) confirmed scans showed a small chip of cartilage in Cooper's right knee and the playmaker would need an operation "to clean up" the problem.
Having only recently returned for the Wallabies, Cooper will miss Australia's final two games of the competition in South Africa (on September 29) and Argentina the following weekend.
However, Cooper's injury is not long term and he may be available for the end-of-year tour to Europe.
The injury compounds a troublesome season for Cooper, who put in one of his worst Test efforts of his 38-cap career in Australia's come-from-behind win over Argentina last Saturday.
The Queensland playmaker made a string of errors that contributed to Australia trailing 19-6 before they rallied late to win 23-19.
Australia will name a 28-man squad for the matches against the Springboks and Pumas on Wednesday.