Waldrom's opportunity is Vunipola's exit

England number eight Billy Vunipola has been replaced by Thomas Waldrom in the squad preparing for Saturday's QBE International against Australia because of concussion.

Vunipola took a blow to the head in Saracens' 31-24 Aviva Premiership defeat by Northampton on Sunday and has been ruled out of contention against the Wallabies.

The number eight was dropped for the 28-9 victory over Samoa at Twickenham - Ben Morgan started in his place - and was unlikely to figure in the climax to the autumn.

"Billy will undergo the graduated return to play protocol at his club," read a statement released by England.

While Waldrom is not expected to feature against Australia, his inclusion among the 34 players called up to England's Pennyhill Park training camp is reward for the strong form shown for second-placed Exeter.

Fly-half Stephen Myler is in the squad after recovering from a hamstring strain, while his Saints team-mate Courtney Lawes is being treated for a knee injury that could sideline him for the visit of the Wallabies.

If Lawes fails to recover in time, Dave Attwood and George Kruis will start with Graham Kitchener offering cover from the bench.

Head coach Stuart Lancaster names his matchday 23 on Tuesday evening and has already stated he will keep changes to a minimum.

Blindside flanker James Haskell had a quiet game against Samoa so could make way for Tom Wood when Lancaster announces the starting XV on Thursday morning, but the most intriguing selection will be at inside centre.

George Ford's superb full debut demands his retention against the Wallabies, leaving Owen Farrell to battle it out with Billy Twelvetrees and Kyle Eastmond for the number 12 jersey.