Teddington - Australia gave key No 8 David Pocock a final chance to prove his fitness on Friday before naming a team for the Rugby World Cup semi-final against Argentina.
"He has improved and did a little bit extra this week. We will watch him on the paddock and hope he does a full session later," said coach Michael Cheika explaining a delay in naming his starting XV for Sunday's game.
Pocock injured a calf muscle in Australia's final Pool A win over Wales and missed the quarter-final victory over Scotland.
The two-time champions also have doubts about star fullback Israel Folau who has an ankle injury and prop Scott Sio who hurt an elbow against Scotland.