England coach Martin Johnson says he will hedge his bets over injuries to other players during Saturday's game with Romania before adding stand-by player Thomas Waldrom to the squad.
Leicester forward Waldrom has been called up as cover for Nick Easter, who is struggling with a back problem, but he has not yet formally been added to the squad.
Prop Andrew Sheridan has already been ruled out of the tournament because of injury, but Johnson has not yet named his replacement, so technically England currently have a 29-man squad.
"When we had the five props intially it was a bit top heavy but there was always a risk of someone getting hurt," said Johnson.
"It's happened unfortunately, it left us in not too bad a position.
"Hopefully we don't have to rush into anything and hopefully everyone's fit and healthy to train on Monday in Auckland (after the Romania game) but in my rugby experience it's best to be aware of all eventualities."
Johnson also said he was keen to give all his squad players a run-out to get match practice, in case more injuries thrust them into the spotlight - Mark Cueto will start against Romania, and David Wilson and Lee Mears can expect an appearance from the bench.
"If they'd come off a big long season it may be different but they have't got a lot of game time," said Johnson.
"If you're going to play one of the biggest games of your career you need some background in terms of being on the field.
"Everyone needs to be ready all the time - we've had late injuries last week and four weeks ago in Ireland, it can happen."
Johnson said he saw plenty of potential in England's much-criticised display against Georgia and it was now up to the team to give themselves a better platform to exploit these positives.
"I thought last week when we attacked we were pretty dangerous but we didn't have enough opportunities, what with the penalty count and error count," he said.
"We're going to come out and perform no matter what team they have, and we've got to play at a certain level. It's a bit dictated by them, how they handle it and how we handle them. We've got to set our sights high and play better than we did last week."
Captain Lewis Moody also said he did not think there would be a hangover from the Georgia game.
"We spoke after the game last week about the areas which frustrated us a bit and we've addresed them," he said.
"The guys have been brilliant - from 1-30, the reaction in training has been exactly spot on."