Ulster backrower Chris Henry has been ruled out of Ireland's remaining autumn Test matches with a hamstring injury.
Leinster's Shane Jennings has been called up take Henry's place.
Henry's Ulster teammate, winger Tommy Bowe, has a bruised calf following Ireland's 40-9 victory over Samoa, and Leinster's Luke Fitzgerald has been called up as cover.
Outhalf Jonathan Sexton is expected to return to training today.
The Australia squad arrived in Dublin yesterday ahead of Saturday's clash with Ireland at Aviva Stadium.
Meanwhile, Samoa's George Pisi has been cited for for an alleged dangerous tackle on Tommy Bowe in the 39th minute of the match against Ireland.