James Mortimer 22.Aug.2012Getty Images
Sydney born Kepu, who played for Wesley College in Pukekohe, also represented New Zealand at age grade level.
A former number eight, Kepu has sustained a grade two strain to the medial ligament of his right knee, suffered during a training session in Sydney this afternoon during scrum training.
It is unknown how long Kepu will be out of action, with the 17-test cap prop likely to be replaced by James Slipper.
Slipper was propping cover on the bench at ANZ Stadium during the All Blacks 27-19 win.
Ben Alexander is another option, with the Brumbies prop the second most experienced front row forward in Australia, with 46 test caps and over 50 Investec Super Rugby caps.
However it will not only be the Wallabies who field a new front row, with Tony Woodcock being replaced after he was ruled out with a rib injury.