Alkass Digital
Pat Cummins will be sidelined for six weeks due to a wrist injury sustained in the Ashes but should return for Australia's one-day international World Cup campaign.
Cummins, 30, fractured his wrist in the final Test at The Oval when England won by 49 runs.
Australia retained the urn after drawing the series 2-2.
"Cummins has an undisplaced fracture of his left radius," chairman of selectors George Bailey said.
"We expect him to join the squad during the South African ODI series. We view a period of enforced rest for Pat as a positive ahead of this important World Cup campaign.
"There are still a number of games he could play before the World Cup which is more than enough for him to have a strong preparation."
Cummins was named Australia's ODI captain in 2022 and has skippered the national side on two occasions.
He sustained the wrist injury while diving in the field on day one of the fifth Test but played through the following four days.
Australia play three T20Is and five ODIs against South Africa between 30 August and 17 September, and they have three ODIs lined up against India between 22-27 September.
The 2023 ODI World Cup begins on 5 October in India with Australia kicking off their campaign against the hosts in Chennai on 8 October.
Mitchell Marsh has been named as Australia's T20I captain for the series in South Africa in Cummins' absence.
Marnus Labuschagne is the most notable omission from the extended 18-player ODI squad, having featured in each of Australia's last nine ODIs and 30 of the last 38 since making his debut in 2020.
The 29-year-old was part of the squad that won a three-match series in India in March.
The uncapped duo of leg-spinner Tanveer Sangha and all-rounder Aaron Hardie have been named in the squad, which will be trimmed down to 15 nearer to the start of the World Cup.
Marsh, Cameron Green, Marcus Stoinis and Sean Abbott are the leading seam-bowling all-rounders, while Ashton Agar, Sangha and Adam Zampa offer spin options.
All-rounder Glenn Maxwell will miss the South Africa leg as he expects the arrival of his first child.