Jonathan Joseph (AP)
Bagshot - England are waiting on the fitness of centre Jonathan Joseph and back-row forward Ben Morgan as they prepare for their crunch World Cup match against Wales on Saturday.
Joseph suffered a blow to his chest during England's 35-11 opening win over Fiji at Twickenham last week. Morgan is trying to overcome a knee injury.
England are to announce their team to play Wales on Thursday.
"Jonathan has a bit of a knock, nothing too serious and our medical staff are working extremely hard behind closed doors to get him fit for selection," England backs coach Andy Farrell told reporters at England's training base in Bagshot, southwest of London, on Tuesday.
"We will give him every chance to put an England shirt on this weekend.
"It's something and nothing. He has got a knock on his chest. If he is fit for this weekend, we will know by tomorrow (Wednesday) internally. If he is not fit it will not be more than a week anyway probably.
"Ben has a little bang on his knee that isn't serious at all.
"We don't need to rush. We need to take our time and give everyone the best possible chance of being fit."
The 24-year-old Joseph, with five tries in 14 Tests, has become England's main attacking threat in midfield. It would be a blow to England were he ruled out of the match against injury-hit Wales, who beat Uruguay 54-9 in their World Cup opener on Sunday.
If Joseph is sidelined, England could bring in rugby league convert Sam Burgess to partner Brad Barritt in midfield or opt for the guile of Henry Slade.
Playing Owen Farrell, a Saracens team-mate of Barritt's and Andy Farrell's son, at inside centre is also an option if England want to field a combination that has had game time together.
"Everyone gets super-excited about the partnership of the centres. But the balance is not just for the backline it's for the team," said Andy Farrell, himself a former England midfielder after changing codes from rugby league.
The back-row situation appears more straightforward, with Billy Vunipola, who impressed as a replacement against Fiji, likely to start at No 8 if Morgan is ruled out, with James Haskell coming on to the bench.