Latrell Mitchell's illness has ended his World Cup campaign, while James Tedesco has been added to Australia's bench for the final against New Zealand.
Coach Kevin Walters initially named the same lineup and left Tedesco out of the 19-man squad, before confirming Mitchell's withdrawal on the team sheet.
Mitchell had been an unused substitute against Samoa, and was reportedly unwell earlier in the tournament.
Tedesco had appeared against Fiji, but was left out against Samoa as Reece Walsh remained Australia's preferred fullback.
The Roosters player returned to the Kangaroos this year after being dropped for Dylan Edwards, while Walsh impressed during Australia's run to the final.
Tedesco's place on the bench gives him a chance to play, possibly if Walsh is injured or Australia need to chase the game.
Before the Samoa semi-final, commentators Greg Alexander and Jimmy Smith argued that Blayke Brailey would offer better cover, while utility Ethan Strange could cover the halves and centre.
"The only cover for Harry Grant is Ethan Strange, but he doesn't play dummy-half," Alexander said on SEN Radio.
Smith proposed moving Tom Trbojevic to fullback if Walsh was injured, with Mitchell at centre and Bradman Best on the wing.
"You don't need James Tedesco. He's a fullback and fullback only," Smith said. "But if Harry Grant gets injured in the first three minutes, you're under pressure for the rest of the game."
Alexander added: "I would see no sense in not having Brailey on that six-man bench."