Wallabies prop Allan Alaalatoa has been ruled out of next weekend’s Rugby Championship clash with Argentina due to injury.

Alaalatoa took a knock to his left knee during Saturday night’s 23-17 win over South Africa, which scans revealed as a medial ligament strain.

The 22-year-old was wearing a knee brace as the team arrived at Brisbane Airport on Sunday morning – but instead of flying with his teammates to Perth, he’ll head to Sydney for further treatment.

The injury is not considered serious but it could also put him in doubt for the trip to Pretoria to face the Springboks in the Rugby Championship’s penultimate round later this month.

Front-rowers Toby Smith and Tom Robertson have been called into camp as cover for Alaalatoa, who was making just his third Test appearance.

“It’s unfortunate but it’s good to have those guys ready to roll,” defence coach Nathan Grey told reporters on Sunday.

“He’s been among a number of new guys who’ve come into that Wallaby set-up and really performed well.

“That’s what we want from all the guys coming in is to deliver their strengths.

“I think our scrum was very consistent last night and quite dominant and having those big blokes at the forefront of that was critical.”

Waratahs rookie Robertson, 22, could perhaps be considered the frontrunner to replace Alaalatoa.

While uncapped, he was included in Australia’s original squad for the Rugby Championship ahead of four-Test forward Smith.

Speaking after the drought-breaking win over South Africa, which snapped a six-match losing streak, Cheika flagged the likelihood of more players making their international debuts before the Spring Tour.

“We’ve got a lot of young guys and we’ve got to get them the experience they need,” Cheika said.

“There’ll probably be a couple more (playing) before the Rugby Championship is out, as well, so we’ve got to get them up a level because I think we have to play up a level as well.”