Australia captain Will Skelton could miss the rest of the Rugby World Cup after suffering a calf injury in training.
The La Rochelle lock has been named in the Wallabies side for Sunday's meeting with Fiji in Saint-Etienne (live on RTÉ2 and RTÉ Player), but has been sent for a scan on the calf issue suffered in training on Thursday.
Head coach Eddie Jones said his skipper would be given until kick-off to prove his fitness for Sunday's Pool C clash at Stade Geoffroy-Guichard.
However, Australian outlet The Roar have reported that there are real fears that the 31-year-old's tournament is over, with concerns he has suffered a calf tear rather than just a strain.
"At this stage, he's still in the team," Jones told reporters at the team hotel without elaborating.
Jones has already lost vice-captain and starting scrum-half Tate McDermott to a head knock, while powerful tighthead prop Taniela Tupou has a hamstring strain which Jones said would keep him out for a couple of weeks.
Evergreen Wallabies prop James Slipper will step into the breach in the front row, switching from loosehead to starting tighthead after recovering from a foot injury.
Co-captain as recently as July, the 34-year-old might also be required to step up into a leadership void as he plays his 132nd test and becomes the third Australian after George Gregan and Adam Ashley-Cooper to play in four World Cups.
"It's a remarkable achievement to play for World Cups particularly as he started off as a tighthead and volunteered to loosehead and now he's volunteering to go back to tighthead," Jones added in one of his few lengthy answers.
"It's a real testament to his to courage, to his resilience, to how much he loves the game and loves playing for the Wallabies. We think on Sunday, he'll play a pretty good game for us."
Having beaten Georgia 35-5 in their opener last weekend to snap a five-match losing streak, the twice world champions could all but secure a place in the quarter-finals with a victory.
Jones spoke again at length about how he felt World Rugby's focus on player safety had turned the game into a series of "30-second bursts of power" interspersed with two-minute spells of extremely rapid transition.
"When you play against Fiji, you'd always like to have set-piece advantage," he added.
"The power contests will be interesting, they've got a very big pack but we want to take them on in that area. Then in the transitional, we've got to be one step ahead of them, one step ahead."
In his team, Jones selected the experienced Nic White at scrum-half instead of McDermott, with rookie Issak Fines-Leleiwasa set to win his second Test cap from the bench.
Fines-Leleiwasa is one of six players with Fijian heritage in the matchday squad, along with number eight Rob Valetini and backs Samu Kerevi, Marika Koroibete, Mark Nawaqanitawase and Suliasi Vunivalu.
Lock Nick Frost returns to the starting line-up in the second row after missing the last two Tests because of a cut to his ear, with Richie Arnold likely to step up from the bench if Skelton is ruled out.
Additional reporting: Reuters
Australia: Ben Donaldson; Mark Nawaqanitawase, Jordan Petaia, Samu Kerevi, Marika Koroibete; Carter Gordon, Nic White; Angus Bell, David Porecki, James Slipper; Nick Frost, Will Skelton (capt); Tom Hooper, Fraser McReight, Rob Valetini
Replacements: Jordan Uelese, Blake Schoupp, Zane Nonggorr, Richie Arnold, Rob Leota, Issak Fines-Leleiwasa, Lalakai Foketi, Suliasi Vunivalu
Watch Ireland v Tonga (Saturday 8pm), South Africa v Romania (Sunday 2pm) and Australia v Fiji (Sunday 4.45pm) on RTÉ2 and RTÉ Player, with coverage of every Rugby World Cup game on RTÉ Sport Online and the RTÉ News app.
