Farrell ruled out of England side
The 32-year-old former Great Britain rugby league captain injured his right calf muscle in training on Wednesday.
England will not name their replacement until Friday, with Olly Barkley, Mike Catt or Dan Hipkiss set to come in.
Bath star Barkley would be favourite to regain his place, having been dropped after England's win over Samoa.
Barkley and Leicester's Hipkiss were both named on the bench for Saturday's match but England coach Brian Ashton could opt for the greater experience of 2003 World Cup winner Catt.
The 36-year-old could come on as a straight replacement to partner Mathew Tait, or at fly-half with Jonny Wilkinson moving to inside centre.
Hipkiss is more of an outside centre and his call-up would lead to a rejig of the midfield.
Farrell replaced Barkley after an hour in the 36-20 win against Tonga and went on to score his first try in an England shirt.
His physical presence and powerful kicking game earned him a starting place in the England midfield against the Wallabies.
"For this game we need the direct approach that Andy Farrell brings," said England coach Brian Ashton when announcing his team on Wednesday.
"He's looked sharper and sharper as the tournament has gone on."
Wilkinson, himself to stranger to injury, said Farrell's strength of character would be missed.
"It's not ideal scenario for a team to have to announce a player not making a game. It's tough for Andy himself," he said.
"Andy's had a fantastic tournament so far, off the field especially, what he's brought to the squad in terms of solidity and consistency in attitude and his performance against Tonga summed it up.
"It is a disruption but the strength and depth in the squad means we can overcome that quickly and get on with it."
Former Wigan rugby league star Farrell has endured a frustrating time since switching codes in a move funded by Saracens and the Rugby Football Union in 2005.
He missed his entire first year in union because of injury and was briefly tried at flanker before being moved to the centre position.
|