The players have been given permission to skip the first game of the series after helping their side to the SA20 title with victory over the Pretoria Capitals in the final at Newlands on Saturday.
Wicketkeeper-batter Lhuan-dre Pretorius and seamer Eathan Bosch have been called into the squad for the match at Boland Park only.
The Sunrisers trio will be back for the second and third games on Thursday and Saturday respectively.
The Proteas players not involved in the SA20 final gathered over the weekend to begin their campaign.
“The boys are still coming in drips and drabs at the moment, so I think it'll be good once we're all connected and we're all together,” Markram told reporters on Monday.
“Obviously, it is a bit different to SA20, but I feel like everyone's in a really good space, informal conversations on the buses and stuff, and everyone's sort of feeling that same good energy.
“Quite a few of the guys have done well (in the SA20) and are showing some really good signs. So you'd much rather be in that space as a team than maybe sitting with a few guys that have been struggling, so we're blessed that the boys are looking really good.”
Markram says easing players back into the mix who have been involved in an energy-charged final ahead of the T20 World Cup in India and Sri Lanka is important, to give them a mental and physical break.
But at the same time, it is important to work on combinations and ensure everyone is up to speed.
“You just have to manage where each guy is at. Some guys played literally last night (Sunday), and you don't want to risk them running out tomorrow (Tuesday),” he said.
“For example, if they feel the need to rest, some guys are keen to play and then, by all means, they're on the park and they're involved, but we kind of have an understanding of where each guy fits in and how it all affects the rest.
“So combinations, I think, we’re fine. It's now just trying to get them exposed to that role and time in the middle of doing what's needed of them in that role.”
Big-hitting batter David Miller must still prove his fitness before he is considered for the World Cup squad.
South Africa open their World Cup campaign against Canada on February 9. They also have Afghanistan, New Zealand and the United Arab Emirates in their pool.
