Australia flanker David Pocock has been ruled out of Saturday's clash with England.
Pocock had been due for a return to action at Twickenham after recovering from knee ligament damage. But scans confirmed that the openside flanker had suffered a calf strain, ruling him out of the England encounter.
Australia will also be without lock Kane Douglas, who played in Saturday's 33-6 defeat to France but has developed a knee injury.
The Wallabies' second-row stocks will be hit further tomorrow if Rob Simmons is found guilty of the dangerous tip tackle he was cited for after the Paris match.
Chris Ashton has replaced Ugo Monye in England's 23-man squad. The Saracens wing was suspended for the 54-12 victory over Fiji last weekend but has been recalled to face the Wallabies, against whom he has scored three tries in three Tests.
The inclusion of Ashton is the only change made by head coach Stuart Lancaster, who has decided not to rush Jonathan Joseph or Alex Corbisiero back after injury.
Wasps lock Joe Launchbury is pushing hard for a first Test start while Thomas Waldrom appears to have retained the No 8 shirt after Ben Morgan was among 13 players released.
Manu Tuilagi has not trained this week because of a sprained foot, but England are confident he will be fit to play.
Jones, Turnbull in double Welsh blow
Second-row Alun-Wyn Jones (shoulder) and flanker Josh Turnbull (knee ligaments) will take no further part in an autumn series that also includes appointments with New Zealand and Australia.
Jones went off during the first half of last Saturday's 26-12 defeat against Argentina and has undergone a scan that will now sideline him, while Scarlets forward Turnbull was also hurt in the Pumas clash.
Hernandez hopes to be fit for Dublin
Argentina have made three changes to face France in Lille on Saturday, two enforced by injuries to Felipe Contepomi and Juan Martin Hernandez in last weekend's 26-12 win over Wales.
Marcelo Bosch, ever-present during the southern hemisphere's Rugby Championship that ended five weeks ago, joins Gonzalo Tiesi in the centre in place of Contepomi, whose knee ligament injury has ruled him out for the rest of the tour.
Lucas Gonzalez Amorosino comes in at full-back for Hernandez, who is recovering from leg muscle fatigue but could be fit for Saturday week's Test in Dublin.
Horacio Agulla lines up on the right wing in place of the rested Gonzalo Camacho.