Tom Roberston set for an extended spell on the sidelines

Waratahs and Wallabies prop Tom Robertson may be out of Australia’s Rugby World Cup plans after suffering knee injury in Argentina.

The front rower suffered the injury during the Wallabies last on-field session in Buenos Aires ahead of the clash with Los Pumas this weekend.

Roberton's injury is expected to keep him sidelined for an extending period of time which may rule the 24-year-old out of the showpiece in Japan next year.

Wallabies coach Michael Cheika spoke of his concern on the suspected ACL tear 

“I’d say he’s done a significant knee injury,” Wallabies coach Michael Cheika told reporters. “I won’t pre-empt scans or anything like that but it’s not looking ideal.”

“It was nothing. Just a very innocuous event, no contact, nothing. It looks significant.

“He’ll stay with us now, there’s no point sending him home yet, and when he gets home he’ll get the scans he needs and then I’d imagine, the operation he needs after that.”

Robertson hasn’t started for the Wallabies since the first Bledisloe Cup Test in Sydney, and has been left out of Michael Cheika’s matchday 23 for Australia’s last two fixtures.