Former Newcastle Knight Cooper Vuna looks set to become the latest league convert to make his Wallabies debut after a training injury put Joe Tomane in grave doubt for Saturday night’s clash with Wales.

Fellow code-switcher Tomane was rushed to hospital for scans during Thursday afternoon’s training session after hurting his left ankle at Ballymore.

He required crutches to help him get into a waiting car and looks a remote chance of playing his second Test, at Suncorp Stadium.

It would end a bittersweet week for the tackle-busting Brumbies flyer who made his international debut in Tuesday’s shock 9-6 loss to Scotland.

Tomane, who switched codes after stints with Melbourne and Gold Coast in the NRL, had limited opportunities in the wet against the Scots but showed great pace to save a try and good signs of his potential.

“We thought he did very well in his first outing,” coach Robbie Deans said before Tomane’s injury struck.

“He made a lot of constructive contributions. He showed the capability he has in terms of speed and strength and evasiveness, and he’s accurate.

“We see a bright future for Joe.”

After struggling in defence in his debut season with the Melbourne Rebels last year, Vuna has been in strong try-scoring Super Rugby form and is poised to join fellow New Zealand-born winger Digby Ioane in the backline.

Queensland Reds Luke Morahan and Dom Shipperley are also in the Wallabies squad and could be potential replacements but Vuna replaced Tomane in training, running on the right wing with the starting side.

Vuna would become the 860th Wallabies player if he starts against the Six Nations champions.

The injury news follows a disappointing medical report for Western Force No.8 Ben McCalman who has been omitted from Australia’s squad as he will undergo shoulder surgery and is expected to miss at least the next two months of rugby, if not the rest of the season.