Maxwell, Smith, Starc, and Cummins are included in the squad of 15.
Players' final roster must be confirmed before September 28.
Despite injury concerns surrounding the crucial four, Pat Cummins, Steve Smith, Mitchell Starc, and Glenn Maxwell have all been nominated to Australia's 15-man provisional roster for next month's Cricket World Cup.
To get fit for the tournament in India, which begins on October 5, all four are skipping the current limited overs tour of South Africa.
The recent Ashes series in England resulted in Captain Cummins breaking his hand, and there are also injury concerns for Smith (wrist), Maxwell (ankle), and Starc (groyne).
The ICC must agree on a final lineup for the 50-over competition by September 28; the four players won't likely participate in the five one-day internationals against the Proteas that begin on Thursday.
However, there is a chance to play in the ensuing three-match ODI series against India, which starts on September 22, according to selectors' chair George Bailey.
"Pat Cummins, Steve Smith, Mitchell Starc, and Glenn Maxwell's return to play plans are on schedule. All are in a good position to reactivate in the future weeks and may be chosen for the forthcoming series against India.
With the senior players included, the group maintains a stable atmosphere; there is no room for those who were given the opportunity to shine in the recent 20-over series in South Africa. Particularly with his 4-31 in the opening T20 international, Tanveer Sangha had a fantastic debut.
The other members of the first 18-man World Cup squad, which was announced last month, were quick Nathan Ellis and all-arounder Aaron Hardie, who also made his international debut last week.
There is still plenty more cricket to be played before the ICC's squad deadline, according to Bailey, so the door is not yet shut.
Before the final selection is to be announced, eight one-day matches in South Africa and India still need to be played, he said. Two World Cup warm-up matches are played immediately after, providing lots of opportunities to continue preparing for the event.
Provisional Australian World Cup squad: Pat Cummins (captain), Sean Abbott, Ashton Agar, Alex Carey, Cameron Green, Josh Hazlewood, Travis Head, Josh Inglis, Mitchell Marsh, Glenn Maxwell, Steve Smith, Mitchell Starc, Marcus Stoinis, David Warner, Adam Zampa.
