Wallabies gun Joseph-Aukuso Suaalii was sent for surgery on a broken jaw

The most expensive signing in Rugby Australia history could be missing from the British and Irish Lions series after a serious injury revelation.

The Wallabies hopes of toppling the mighty British and Irish Lions have been delivered a significant setback after code-swapping former NRL gun Joseph-Aukuso Suaalii was sent for surgery on a broken jaw.

The 21-year-old, who signed a monster $5 million deal to leave rugby league, copped an accidental knee from a Waratahs teammate in Friday’s loss to the Queensland Reds and had to be taken from Allianz Stadium in a medicab.

He was concussed but the Tahs still held out hope he would only miss the mandated period and be back to help his team push for a Super Rugby Pacific finals spot and continuing his preparation for the Lions series.

But scans revealed the star backline flyer would need surgery to reinforce a fractured jaw with a review in four weeks, and only a month before the three-Test series against the Lions begins in Brisbane on July 19, will determine whether he’ll be able to play any part.

“He was monitored and has settled well from his concussion,” a Waratahs statement said.

Joseph-Aukuso Suaalii of the NSW Waratahs is taken off the field injured . (Photo by Matt King/Getty Images)

“However, over the ensuing days he developed soreness which has been subsequently investigated and has shown a small undisplaced fracture of the jaw.

“In consultation with specialists, it has been determined that a small operation to reinforce the area is the best path forward.

“This will result in a review after four weeks and return to play based on that review.”

Waratahs coach said the club would do what it could to get him ready for the Lions.

“We will do all we can to facilitate his recovery in consultation with Rugby Australia to have him in the best shape possible for his availability for the Wallabies,” McKellar said.

Suaalii was set to play a major role for the Wallabies after his stunning Test debut against England last year.

But given his relative inexperience at the top-level, Wallabies coach Joe Schmidt said earlier this week he wanted Suaalii to play as much as possible, without knowing the extent of his injury.

“I’m keen to see him keep playing,” he said.

“He’s missed a few games already this season. He hasn’t had that many games anyway so, for Joseph, it’s important that he just keep playing when he’s fit and available to play.”