LONDON -- England's injury problems are mounting ahead of the internationals in November and December, with centres Jordan Turner-Hall and Jonathan Joseph the latest players in the treatment room.
Flyhalf Freddie Burns and centre Billy Twelvetrees, who both play for Gloucester, were called up as cover in case Turner-Hall and Joseph fail to recover from knee and ankle problems, respectively.
Dylan Hartley and Courtney Lawes are struggling with knee injuries while prop Joe Marler has a hamstring injury.
Thirty-six players linked up at the England squad's base west of London on Sunday, six days before a test against Fiji kicks off a run of four internationals. Australia, South Africa and New Zealand visit Twickenham on successive weekends after Fiji.
England coach Stuart Lancaster names his team on Thursday for the Fiji game.