Scans and additional testing will determine the exact severity in the next 48 hours but given the history of setbacks, Wallabies staff will tread carefully and the latest tweak is likely see him miss the final four games of The Rugby Championship, to be held over the next four weeks.
Wing is one of the few positions the Wallabies boast significant depth but the absence of Vunivalu certainly doesn’t help their cause.
The world champion and British and Irish Lions conquering Springboks await Dave Rennie’s side in Queensland and Vunivalu’s ability to negate the high ball barrage heading the Wallabies’ way would have been invaluable.
The Wallabies are also sweating on the fitness of James O’Connor.
Injuries have cruelled the star playmaker’s entire Test season, leaving Noah Lolesio as the best of few options at five-eighth.
O’Connor will be assessed by team medical staff at Royal Pines on Tuesday but he is more likely to be available for selection next weekend.
“We’ll wait and see how he presents when we get back to Queensland. He’s been in Queensland, training hard,” McKellar said.
“Obviously, it’s been difficult for him without having any rugby training, as such, there is so only so much running and running conditioning you can do, and individual skill work.
“He will need to get back into rugby training but we will see where he’s at in the next couple of days and Dave and the selectors will make a decision.”
While the Wallabies may be tempted to turn to Reece Hodge or Matt To’omua at five-eighth in O’Connor’s likely absence, McKellar backed Lolesio to bounce back after a string of sub-par performances against the All Blacks.
“I’m really proud of Noah. We just have to understand that he’s finding his feet at this level,” McKellar said.
“You look at Richie Mo’unga five years ago, he certainly wasn’t the player he is now.
“We have to be patient, make sure we coach him well, develop him and make sure he gets to that level as soon as we can and just hope the general public can be patient with him as well.
“It’s a tough position to play in any team. Particularly for the Wallabies against New Zealand and South Africa. There’s no harder task.
“So, we have to be realistic. He’s a really good young footballer who’s developing. He’ll get there.”