Cricket Australia has held talks with South Africa over the prospect of hosting the Proteas in a five-Test series for the first time in more than 60 years.
Test-playing nations are awaiting the release of the next Future Tours Program for 2027 to 2031, as well as an indication of what the four years look like after that.
It is anticipated the World Test Championship will increase from nine teams to 12 for 2027-29, while the number of bilateral ODIs could rise and fall around global events.
Also at play is Australia, England and India all being keen to face a fourth team in five-Test series, with South Africa a favoured option.
That will not come easy for Australia, given South Africa's home summer runs at the same time.
But Cricket Australia (CA) chief executive Todd Greenberg is in South Africa for this month's tour, and has broached the subject after the last five-Test series was 1966-67.
"We would love to host South Africa for a five-Test series," Greenberg said.
"There's a real challenge on that between our organisations because they play in a similar period of the year. I can understand that.
"It would be like asking us 'can we come and play in South Africa during December and January?'
"Our answer would be no, because we're protecting our window.
"But we're in constant conversations with them. I'll have conversations while I'm here with them."
South Africa did not host home internationals in November or December last year, but have the January-February window blocked out for the lucrative SA20.
The earliest possible summer in Australia would be 2030-31.
The next two seasons loom as lean and disjointed ones for Australia, with an India tour putting the team on the road the day after January's Sydney Test this summer.
Pakistan will then tour for three Tests in late December and early January next summer, before Sri Lanka arrive for two more in February after the BBL break.
Bumper home summers against India and England then follow in 2028-29 and 2029-30.
If South Africa were to become five-Test opponents, that would effectively leave just one summer for nations outside of them, India and England to tour every four years.
But Australia want to make more use of Top-End matches in winter, while Greenberg has long been of the opinion the number of Test-playing nations will shrink due to affordability.
"(It's not just) putting on Test matches. It's the ability to invest in your system to create a structure for red-ball cricketers," he said.
"In other countries, they're really struggling to create that level of investment, which makes Test cricket very, very hard to achieve.
"I think there is a world where there'll be member nations who don't play Test cricket. Or they might have to play more away Test cricket than they do at home."
Meanwhile, the anticipated increase to 12 teams in the Test Championship could present a situation where Australia are drawn to face Afghanistan.
Australia have not faced them in bilateral matches since the Taliban takeover of the country, while opting not to boycott them in ICC events.
"We'd have to think about it (whether we would play them)," Greenberg said.
"That's not something we've talked about. We'd have to have an open mind to how that would work."
