Proteas coach Shurki Conrad admitted after the defeat in Durban that his batters were mentally beaten in the 214-run loss, with a quick turnaround to the second Test in Gqeberha.
In better news for the home side, South Africa are expected to welcome strike-bowling quick Kagiso Rabada back from a hamstring tear for Sunday's second Test, with Conrad declaring he hoped his "Rolls Royce will be purring down the highway" again.
Middle-order batter Stubbs has immediately paid the price after scores of 32 and 1 in Durban, while Verreynne remains in the squad but appears unlikely to play after South Africa confirmed Ryan Rickelton would wear the gloves.
Conrad had said he was "pulling the very last strands out" of his hair over the Proteas' decision-making in Durban, with batters guilty of throwing wickets away in the 214-run loss.
The Proteas coach also pleaded with batters to use Aiden Markram's patient fourth-innings 75 as an example to learn from, and preached "single-bloody-mindedness" for the next Test in Gqeberha.
"We obviously need to look at how can we improve the side without being knee-jerk in our reactions," Conrad said after the loss.
"We need to show composure.
"But the question is always, 'will it make the boat go faster if we make changes, or will it slow the boat down?', and we are constantly looking at how we make the boat go faster.
"It doesn't mean you now have to go soul-searching or questioning all the things we have done really well and are doing really well. We just need to get bloody better.''
Conrad did point to the Proteas' 10-month gap since their last Test as a possible reason for the poor showing.
But he was also left frustrated with the way his side routinely kept Australia interested by giving away wickets, rather than entering the grind in the same way Matt Renshaw did.
"Dismissals in the batting sit in one of three categories. It's either technical, tactical or mental," Conrad said.
"And if we're brutally honest, a lot of our dismissals sat in the mental. Is that an easier fix than technical and tactical? Probably not.
"We haven't played in a while, you come up against arguably the best attack in the world on a really good wicket, and they challenge you in so many respects.
"Every time we felt we were just getting ourselves out of the woods, we would let them back in."
