Polota-Nau was among a handful of big names who are not travelling with the Wallabies to South Africa and England for the final two games of the Rugby Championship, as injury and fitness concerns take their toll on Michael Cheika's Test squad.

The Waratahs hooker has been nursing an arm injury for much of the year and will sit out the next two weeks before making a decision about whether he needs further surgery. It has left his Test future under a cloud given widespread speculation he will head offshore to sign with an English Premiership club. With 68 Tests under his belt, Polota-Nau will be eligible under the Giteau Law to be selected from overseas, but if further surgery is needed the long-time Waratah could miss the rest of the season.

"He had a second break on his arm this year and the repair hasn't done what we would have liked it to do," Cheika said.

"He's still got pain, he's really been making sacrifices for the team ... That's enough now, let's get another guy going in that spot, let him heal properly, because what he's been adding in games has been vital for us. He's a player we want in top condition going forward. His decision to either have a rest or operate, whatever it might be, which he'll make in the next couple of weeks, we'll decide then what happens to him then."

One of Polota-Nau's understudies at the Waratahs, Tolu Latu, was called up in his place, beating in-form Reds hooker Andrew Ready for the spot. Cheika said he had spoken to Ready about what he wanted the young Queenslander to improve on, and had been impressed by Latu's form in the NRC.

Will Skelton, Ben McCalman and Drew Mitchell also missed out on spots, alongside injured players David Pocock (hand) and Matt Toomua (concussion). Latu (Waratahs) and winger Sefa Naivalu (Rebels) were the two uncapped players included in the touring squad, while Brumbies winger Henry Speight was also called in.

Cheika said he was pleased to see depth improving in Australia's wing stocks after relying on non-specialists for many years.

"We've also got Taqele [Naiyaravoro] who's in Japan to come back, [NRL player Marika] Koroibete at the end of the season, he could be an option, and there's a few outside backs in general coming through ... we're starting to build up nicely in those outside back areas," Cheika said.

The Springboks, meanwhile, are welcoming back big names, with five-eighth Pat Lambie and fullback Willie Le Roux named for South Africa's final two matches against Australia and New Zealand. Cheika said Le Roux's return would boost the struggling Springboks, who have battled to find form and the right combinations this season.

"That's definitely going to be something to have a look at for us, because he's a very handy player," he said.

The Wallabies, who have won their past two Tests, leave for South Africa on Saturday. They play the Springboks in Pretoria on October 1 then face the Pumas at a historic offshore clash at Twickenham on October 8.

Wallabies squad: Allan Alaalatoa, Rory Arnold, Adam Coleman, Quade Cooper, Kane Douglas, Scott Fardy, Israel Folau, Bernard Foley, Nick Frisby, Will Genia, James Hanson, Dane Haylett-Petty, Reece Hodge, Michael Hooper, Sekope Kepu, Samu Kerevi, Tevita Kuridrani, Tolu Latu, Sean McMahon, Stephen Moore (c), Luke Morahan, Dean Mumm, Sefania Naivalu, Nick Phipps, Tom Robertson, Rob Simmons, Scott Sio, James Slipper, Henry Speight, Lopeti Timani.