The Wallabies have called up Leroy Houston after back rower Ben McCalman was ruled of the third Test in Sydney with a broken shoulder.
McCalman became the second Wallaby No.8 to suffer a serious injury in as many weeks after fracturing his scapula in the second Test against England in Melbourne.
The tough forward bravely played out the match but is expected to be sidelined for 4-6 weeks, which is a blow to the Western Force but should see McCalman back in time for the opening Bledisloe Cup clash on August 20.
Houston flew to Sydney to join the Wallabies camp, and Liam Gill and Wycliff Palu are already with the squad. Gill was close to getting a run in Melbourne.
David Pocock has already been lost for the series with a fractured eye socket.
"He (McCalman) has a small crack in his scapula. He will be out for 4-6 weeks, or so," Wallabies coach Michael Cheika said.
"He hurt himself in the first play he came on so he didn't really get a chance to do what he does. He has always proved when I have been involved he is a serious campaigner."
Eddie Jones suggested Cheika would review the selection of Sean McMahon at No.8 but despite flagging "a few changes" for the third Test, the Wallabies coach didn't have any major concerns about the backrow.
"I wasn't unhappy with the backrow last week," Cheika said.
"There were a few basic errors but I thought they worked hard."