England number eight Billy Vunipola has been ruled out of Saturday's clash with Australia at Twickenham Stadium due to concussion.
The 22-year-old suffered the problem during Saracens's 31-24 defeat to Northampton Saints on the weekend.
Exeter Chiefs forward Thomas Waldrom has replaced Vunipola in the 34-man party named by coach Stuart Lancaster.
Northampton fly-half Stephen Meyler returns to the squad after a hamstring issue, but club teammate Courtney Lawes is doubtful for the match as he receives treatment for a knee injury.
England will continue to monitor Lawes's injury situation before making a decision on his fitness later in the week.
