De Zorzi limped off the field while the Proteas were fielding in Potchefstroom and did not come out to bat in the second innings and, following subsequent scans, has been diagnosed with a "mild left hamstring injury".
The 29-year-old would have competed for one of the middle-order batting spots in the Proteas line-up and could still come back into contention for the remaining two Tests in the three-match series.
The Proteas management have decided not to call up a replacement for the left-handed batter after initially selecting an 18-man preliminary squad, that will be cut to 15 ahead of the Test that starts in Durban on Friday.
De Zorzi is the fourth Proteas player to be ruled out with a hamstring injury after pace bowlers Lungi Ngidi, Ottneil Baartman and Kwena Maphaka.
Kagiso Rabada also had hamstring trouble while doing winter training, but indications are that the paceman is on track to be ready to face Australia but will be fully assessed after a two-day intra-squad game that will start in Chatsworth on Sunday.
The Proteas will not want to risk any players, especially bowlers, with a heavy home schedule this summer that will include incoming tours from Bangladesh and England following the Australia series.
Anrich Nortje has admitted he is getting "goosebumps" at the prospect of wearing the Test cap again as he prepares for a possible return to South Africa's starting XI against Australia.
The Proteas will kick off their 2027 World Cup campaign against New Zealand at Newlands on 9 October next year after the ICC revealed the fixtures for the global showpiece.
Australian stars Cameron Green and Matt Renshaw appeared to have added their names to the growing injury list during the third and final ODI against the Proteas on Wednesday night.
Australia avoided a 3-0 ODI series defeat as rain brought South Africa’s chase to an early end in Potchefstroom on Wednesday.
