Australia forward David Pocock will miss the remaining two Tests of the series against England after fracturing his eye socket in Saturday's defeat.
The number eight was injured in a collision as England won 39-28 for a first win over Australia in Brisbane.
"If we want to bring in almost a like-for-like player, then we'll go with Liam Gill," coach Michael Cheika said.
"We have options with experience, so we're fortunate but it's disappointing to lose a player of David's quality."
Pocock, 28, is regarded as one of the best back-row players in international rugby - he secured more turnovers than any other player at last year's World Cup.
"The skills he brings to the game are superb and there's that dynamic that we have in the back row with himself, Michael Hooper and Scott Fardy," Cheika added.
Pocock, who is expected to be out for up to six weeks, will remain with the squad.
He wrote on Twitter: "Gutted to be ruled out of the rest of the #AUSvENG series with a fractured eye socket. Disappointing but these things happen."
England face the Wallabies in the second Test in Melbourne on Saturday, 18 June before playing the third and final match in the series in Sydney seven days later.
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