O'Connor strained his hamstring at AAMI Park to be ruled out of the final two matches of the season while some mystery surrounds Beale's fitness.
The fullback missed the Wallabies' first three Tests of last month with a shoulder injury and ended the third Test win against Wales with a rib problem.
Melbourne officials have said Beale was in doubt for the African tour with "soreness" and will be reassessed on Tuesday after being having two days rest at home.
If both O'Connor and Beale are out, James Hilgendorf would likely regain the number 10 jersey against the Lions in Johannesburg on Sunday.
Paul Alo-Emile, Rodney Blake, Al Campbell, Tom Chamberlain, Tim Davidson, Gareth Delve, Adam Freier, Mark Gerrard, Nic Henderson, James Hilgendorf, Julian Huxley, Mitch Inman, Lloyd Johansson, Luke Jones, Richard Kingi, Lachlan Mitchell, Stirling Mortlock, Cadeyrn Neville, Jono Owen, Hugh Perrett, Nick Phipps, Hugh Pyle, Ged Robinson, Nic Stirzaker, Cooper Vuna.