Steve Smith and Mitchell Starc will miss Australia's must-win ODI clash with Sri Lanka, after the visitors won the toss and bowled in Colombo.
Australia had been hoping the pair would return on Tuesday, but the pair's absence was prolonged as they battle to come back from injury.
Pat Cummins' return after being rested is therefore the only change to the team that lost the third ODI on Sunday night, with Jhye Richardson dropping out.
Sri Lanka have gone with five spinners for the match, which is being played on the same turning wicket as Sunday's.
Wanindu Hasaranga is back from a groin injury after he took four wickets in his last match, replacing quick Dushmantha Chameera.
The decision means Chamika Karunaratne will act as the sole quick for the hosts.
It comes as Australia continue to battle their own injury issues.
Starc has not played since cutting his finger open in the opening Twenty20 of the tour a fortnight ago, with taping and stitches required.
He has been able to bowl in the nets and has since had the stitches removed, but is unable to wear the taping in the match given it is on his bowling finger.
Smith hurt his quad running between the wickets in the second ODI last week and has missed the two matches since.
Neither of the pair's injuries are considered serious, with Australian officials confident they will not linger into the two-Test series starting next Wednesday.
Aaron Finch's decision to bowl comes after Australia battled to get any turn out of the Colombo wicket under lights and the impact of dew on Sunday night.
Australia have not lost a bilateral one-day series to Sri Lanka since 2010, but at 2-1 down they must win the fourth ODI on Tuesday night to stay in the five-match series.
TEAMS
Sri Lanka: Niroshan Dickwella, Pathum Nissanka, Charith Asalanka, Kusal Mendis, Dhananjaya de Silva, Dasun Shanaka (capt), Chamika Karunaratne, Wanindu Hasaranga, Dunith Wellalage, Jeffrey Vandersay, Maheesh Theekshana.
Australia: Aaron Finch (capt), David Warner, Mitch Marsh, Travis Head, Marnus Labuschagne, Alex Carey, Glenn Maxwell, Cameron Green, Pat Cummins, Josh Hazlewood, Matthew Kuhnemann.
