Tom Robertson of the Waratahs score a try during the Super Rugby Semi Finals match between Lions and Waratahs at Ellis Park Stadium. Photo: Samuel Shivambu/BackpagePix

BUENOS AIRES – Australia prop Tom Robertson's hopes of playing at next year's Rugby World Cup in Japan appear clouded after he suffered a significant knee injury training with the team in Argentina.

The 24-year-old Robertson had not been named in the matchday squad for the Wallabies final Rugby Championship clash with Argentina in Salta on Saturday.

Coach Michael Cheika told Rugby Australia's website they would not be able to determine exactly what the injury was until Robertson had scans upon his return to Australia.

“I'd say he's done a significant knee injury,” Cheika said after the team's training session in Buenos Aires before they travelled to face the Pumas. “I won't pre-empt scans or anything like that but it's not looking ideal.

“It was a very innocuous event, no contact, nothing, so it looks significant.”

Cheika said Robertson would remain with the squad in Argentina.

“There's no point sending him home yet,” Cheika said. “He'll stay with us for the trip and then when he gets home he'll get the scans he needs and I imagine the operation he'll need after that.”

Robertson has been primarily used as a replacement in his 24-test career since his international debut against Argentina in Perth in 2016 but was likely to have been in Cheika's planning for next year's global showpiece.

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The Wallabies have been blighted by injuries during this year's Rugby Championship, with loose forwards Michael Hooper and David Pocock, prop Taniela Tupou, fullback Israel Folau and hooker Tatafu Polota-Nau all affected at some time.

The 2015 Rugby World Cup finalists have struggled in this year's southern hemisphere competition with one win and need to beat Argentina to avoid their first wooden spoon in the competition.