Cooper's Championship over

Getty Images     19 Sep 2012     Getty Images

Cooper underwent scans on the troublesome knee on Tuesday and they showed the 24-year-old has a small chip of cartilage that is causing him discomfort and needs an operation to clean up.

The Queensland Reds fly-half has started in Australia's past three matches in the Rugby Championship but the Wallabies' medical staff have decided Cooper needs the surgery now rather than waiting for the end of the Southern Hemisphere-based competition.

Cooper's right knee was also operated on after the 2011 World Cup but the Wallabies believe another operation will not keep him on the sidelines for long, with the playmaker hopeful of joining Australia's European tour in November.