Australia do not name their team until Thursday but it is understood coach Michael Cheika is set to make a number of changes for the match at Perth on Saturday.
O'Connor's selection at No 13 in place of Tevita Kuridrani is set to be the big talking point, with the Brumbies centre understood to have been left out of the match day 23 altogether.
It caps a remarkable comeback for O'Connor, who played his first game since 2013 for the Wallabies two weeks ago in Brisbane, coming off the bench.
O'Connor has impressed those in the Wallabies set-up with his skill and defence, making his audition at No 13 a little left-field but understandable at the same time. He has never started for Australia in the centres from 45 tests stretching back to 2008.
Samu Kerevi will link up with O'Connor in the midfield at No 12, with Reece Hodge and Marika Koroibete likely to feature on the wing.
Halfback Nic White is tipped to get the nod over Will Genia in the starters.
White had an excellent performance in South Africa despite Australia's loss, while Genia wore the No 9 jersey in Brisbane during Australia's four-point win over Argentina.
Meanwhile, Tolu Latu is set to replace Folau Faingaa at hooker in what is also a remarkable story given his on-field discipline issues as well his drink driving charge earlier this year that many believed had put his World Cup hopes in jeopardy.
The Wallabies have not won the Bledisloe Cup since 2002.