England prop Alex Corbisiero has been ruled out of Saturday's clash with Australia with a knee injury but could return to take on Argentina.
The Northampton star suffered a knee injury against Castres just over a fortnight ago.
Although the problem is not an aggravation of his previous serious knee injury, the game comes a week too soon.
England coach Stuart Lancaster admits the loss of the prop - who performed superbly for the British & Irish Lions against the Wallabies in Australia in the summer - is a blow, but he says there is good cover.
Lancaster told Sky Sports: "He is making good progress and we're hopeful another week's recovery and rehab will see him up and running for the Argentina game.
"It's a big blow but we've got two very good looseheads in Mako Vunipola and Joe Marler. Joe was one of the pick of our forwards in Argentina (during England's summer tour) and Mako has been outstanding this season so it's a good position for us."
Lancaster's lieutenants Andy Farrell and Graham Rowntree were both on the Lions coaching staff in the summer and will provide valuable insight into Australia.
But Lancaster says that they cannot read too much into the lessons learned from the Lions tour because Australia have a new coach in Ewen McKenzie, the replacement for Robbie Deans.
"They did bring back an insight into the individuals that played at the time but I think we have to recognise that it's a different coaching team and a different environment, with Ewen McKenzie who clearly the players are playing for," he said.
"I saw their game against Argentina (a 54-7 victory) and the recent game with the All Blacks (a 41-33 defeat) and they are clearly back to their best now."
The Wallabies beat England at Twickenham last year and Lancaster said: "We were disappointed to lose that game. It's still fresh in my mind. We've got to get all the components to our game right.
"We've got all the players in camp now. By the close of play on Tuesday we will be pretty clear in which way we are going. We want to put a team out that wins on Saturday."