The former Saracens lock was head coach Eddie Jones’ surprise pick as Wallabies skipper for the tournament, but has fully embraced the role.
Skelton picked up a calf issue in training on Thursday however, and will undergo scans on Friday having initially been named in the starting lineup.
“At the moment he’s still in the team,” Jones told reporters.
Australia dispatched Georgia 35-15 to open their Pool C account at the World Cup, but now face a serious test of their mettle under new boss Jones.
The former England chief will hope that Skelton can shake off his new injury concern in time to take on a dangerous Fiji side that so nearly toppled Wales but lost out 32-26 last weekend.
James Slipper, in his fourth World Cup, will start at prop after replacing the injured Taniela Tupou, with Nick Frost back at lock and Nic White in for Tate McDermott at scrum-half.