David Pocock will miss the rest of the Test series against England after fracturing an eye socket.
The flanker left the field late in Australia's 39-28 loss to England in Brisbane.
The longer-term prognosis is still unknown, with medical staff waiting for the swelling on the injury to go down.
Wallabies coach Michael Cheika said he had yet to decide on a replacement.
'We’ve got the option of sticking with what we’ve got or if we want to bring in a like for like, go for Liam Gill [who is not in the 33-man squad]. There’s Ben McCalman, Sean McMahon, there’s options there that have experience in the front line, so we’re fortunate, but at the same time, disappointed.
'We lose the dynamic we have in the back row with himself, Michael and Scott and have to decide whether to create a different type of complementary nature or go like for like.'
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