The Wallabies will be without experienced No.8 Wycliff Palu for the two Rugby Championship Tests in South Africa and Argentina this month.
Palu (32) is suffering from lingering concussion concerns after a September 6 match against South Africa and missed last weekend's 32-25 win over Argentina on the Gold Coast.
Due to Palu's injury history the Wallabies medical staff have advised him to have an extended break.
A team spokesman said the 53-Test loose forward would only return to action once he passes concussion protocols.
It is another concern for the Wallabies after they lost hooker Tatafu Polota-Nau (ankle) in the win over the Pumas.
Wallabies coach Ewen McKenzie is set to announce his 28-man tour squad for the Tests in South Africa (September 27) and Argentina (October 4) on Wednesday.
Queensland Reds No.8 Jake Schatz, brought into camp last week as a train-on player, is in good form after scoring a hat-trick of tries for Brisbane City in the NRC and could be the answer for McKenzie.
A victory over the Springboks in Cape Town would see Australia win back the Nelson Mandela Plate and also leapfrog them on the IRB rankings to only trail all-conquering New Zealand.
Will Genia, now with two NRC matches under his belt in his return from ankle surgery, is expected to tour as a back-up to Nick Phipps cemented the No.9 jersey with his sharp display against Argentina.
The Wallabies are also confident lock Sam Carter will be available despite re-aggravating the ankle problem which sidelined him during the June series against France.
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