Jonny Wilkinson is expected to undergo a scan on Tuesday after turning up for England duty ahead of the forthcoming autumn international campaign nursing a shoulder problem.
The Toulon fly-half is one of five England players struggling with injuries less than a fortnight before Martin Johnson's men tackle New Zealand at Twickenham on November 6.
Wasps pair Riki Flutey and Simon Shaw both have calf problems, flanker Hendre Fourie damaged ribs in Leeds' 6-3 defeat to Sale on Friday night and the Bath tighthead David Wilson has a back injury.
Sale fly-half Charlie Hodgson was called in as cover for Wilkinson while rookie Harlequins prop Joe Marler joined the England squad to deputise for Wilson.
Northampton flanker Tom Wood, Saracens centre Brad Barritt and Wasps' versatile forward Dan Ward-Smith also joined the England squad on Monday.
Wilkinson started the season in prime form for Toulon and is pushing for a return to the England starting XV after losing his place to Toby Flood during last season's Six Nations.
Flood has only just returned from a knee ligament injury and England will announce later on Tuesday whether or not they will release the Leicester fly-half to play against Gloucester at the weekend.
If Wilkinson's injury proves serious, England may decide they cannot risk Flood playing in the Aviva Premiership a week before tackling the All Blacks.
The same applies to Lewis Moody, who has been sidelined for nearly a month with an eye injury but Fourie's injury could force Johnson to wrap his captain in cotton wool.