Rassie Erasmus has confirmed that Siya Kolisi and Ox Nche are the only two players in doubt for Saturday's Rugby Championship opener against the All Blacks at Ellis Park, with both men's availability hinging on how they come through Monday's training session.

Kolisi has been managing a hamstring issue that forced him out of the starting lineup against England in July and was aggravated on his return during the series against Los Pumas. Nche, who suffered a setback in the England match, was left out of the South American tour as a precaution. Erasmus was measured in his assessment of both, describing their issues as niggles rather than injuries and leaving the door open for either to feature.

"If they get through today, they might be good for us," Erasmus said, adding that lock Franco Mostert — who has also been managing his condition — is looking well.

Erasmus will not name his matchday squad until Thursday, the same day Dave Rennie announces his All Blacks selection. He was direct about the reasoning: giving New Zealand as little preparation time as possible against a specific Springbok team shape, and framed the decision as tactical respect rather than gamesmanship.

"The announcement only being on Thursday is to respect New Zealand and knowing how tough this one is going to be," he said. "For this one specifically, we think the less time they have to prepare for our team, the better. So, it's not an arrogance thing; it's respect."

On the fly-half question, Erasmus confirmed two tens will be included in the 23, which suggests a standard 5-3 bench split rather than the Bomb Squad 6-2 configuration for the series opener. With Manie Libbok, Handré Pollard and Sacha Feinberg-Mngomezulu all in contention, Erasmus indicated the full series — running through to Baltimore — would likely see all three used.