England prop Alex Corbisiero has been ruled out of Saturday's Test against the Wallabies at Twickenham due to a knee injury.
The Northampton prop suffered the injury against Castres just over a fortnight ago but England coach Stuart Lancaster is optimistic he will be available to face Argentina on November 9.
The good news is that it is not an aggravation of his previous serious knee injury.
"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," Lancaster told Sky Sports News.
"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."