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.