Australia lose Simmons for Rugby Championship showdown with Bledisloe Cup rivals New Zealand

Lock expected to return in time for Rugby World Cup warm-up in Chicago

Australia's Quade Cooper, left, is tackled by Argentina's Juan Pablo Socino during their Rugby Championship Test match at Malvinas Argentinas stadium in Mendoza, Argentina, on July 25, 2015. Andres LaShow more

Australia were dealt a blow ahead of Saturday’s Rugby Championship decider against New Zealand after lock Rob Simmons was ruled out of the Sydney showdown because of a wrist injury.

The 26-year-old Queensland Reds second row will undergo surgery for a scaphoid injury but should be fit to play in the Rugby World Cup warm-up against the United States in Chicago next month.

“Obviously we’re all disappointed to lose Rob,” Wallabies coach Michael Cheika said on Monday.

"We've been able to build some real depth in the lock position, and Rob's injury presents an opportunity for another player in the squad to stake their claim."

Former captain James Horwill is in line to replace Simmons, who has won 52 caps, and become the line-out caller for the Wallabies.

Simmons is also unavailable for the return Bledisloe Cup fixture in Auckland with New Zealand next week but there are no concerns he would miss the September 18-October 31 Rugby World Cup in England where Australia have been drawn with the hosts, Wales, Fiji and Uruguay in Pool A.

A 24-20 victory over South Africa in Brisbane and a 34-9 win in Argentina last month have set Australia up for a first Rugby Championship title since 2011 and buoyed hopes of a third World Cup triumph.

New Zealand also have a 100 per cent record, but Australia top the table thanks to a superior points difference.

Cheika said that back Matt Toomua and prop James Slipper would need to come through tomorrow’s training session before being cleared to play in Saturday’s clash in Sydney, but utility back Matt Giteau was available after missing the Argentina Test.

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