England number eight Billy Vunipola has been replaced by Thomas Waldrom in the squad preparing for Saturday's QBE International against Australia because of concussion.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.
England 28 Samoa 9 player ratings
England 28 Samoa 9 player ratings
1/16 Mike Brown - 6
Enjoyed scoring his try, unusually a couple of high balls went astray and knocked on during a promising first-half attack. Did not reach the high standard achieved a week earlier against the Springboks.
2/16 Anthony Watson - 6
Far more involved than a week earlier and contributed significantly to Brown's try. A potent threat that England need to use more but still learning the game at elite level
3/16 Brad Barritt - 5
A midfield rock who must still be uncertain what is going on around him. Makes his tackles, attacking ploys limited - grub kicks did not come off - but needs a consistent partner
4/16 Owen farrell - 5
Threw himself into breakdowns with usual gusto but still limited coherence in the midfield attack. Important role in first England try but another game - against better opposition - needed to validate his place
5/16 Jonny May - 7
After nine-minute rest for a blood injury, returned to run straight and true for his first-half try. Second try a walk-in but showed there's no substitute for raw pace and consolidated place
6/16 George Ford - 7
Did well on first start, steadied the first-half ship, kicked goals when it mattered and showed himself an attacking threat with front-foot ball. Made his tackles too for a good evening's work
7/16 Ben Youngs - 5
Undemonstrative return to the starting jersey, oiling the works for others. Greater accuracy with his kicking needed, England are still not testing opponents under the high ball enough
8/16 Joe Marler - 6
Part of a sound scrum which squeezed out two early penalties. Samoa never found a way round this set-piece boulder and Marler showed his customary zeal in loose play, as ball-handler and tackler
9/16 Rob Webber - 6
Another hard-working game, good set-piece work and justified his selection ahead of Dylan Hartley. Did not get his hands on the ball as much as he does at Bath but deserves another opportunity
10/16 David Wilson - 7
Did all of the above and also showed flare as a defender by covering back and stifling a Samoa attack down the left flank. He and Marler left early to give game time to replacements
11/16 Dave Attwood - 6
Another perfect lineout display by England, in which Attwood played full part. Greater first-half fluidity would have given him more chances in loose play and missed a try at the end by knocking on
12/16 Courtney Lawes - 6
Equal contribution to Attwood at lineout time and ran the ball effectively. Can be pleased with his showing after taking that heavy knock against New Zealand first time out
13/16 James Haskell - 6
Typically industrious showing from a player bursting to find a regular starting place. Over-eagerness accounted for concession of penalties but covered the ground well and aggressive in the tackle
14/16 Chris Robshaw - 7
Named man of the match for doing everything he does every week. Important lineout presence and good hands in May's second try, bustled around the field to great effect and made over 20 tackles
15/16 Ben Morgan
Would have liked to make a greater impact. England need more potent running from their big men and though Morgan lifted his game after the break, he became a bit lost as the game broke up
England used all their bench, of whom George Kruis made the greatest impact. The Saracens lock stole one lineout, popped up in midfield more than once and has made a distinct impression. Marland Yarde made one flaring run as May's first-half replacement and returned eager for more but the game had broken up by the time the rest of the bench appeared.
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 match-day 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.