Rabada must sit out the second Investec Test in Nottingham because of an ICC ban for swearing after he dismissed Ben Stokes in the first innings of the tourists' 211-run defeat at Lord's.
Returning captain Faf du Plessis, back after the birth of his first child in time only to watch his team slide to 119 all out in their second innings, must decide whether two seamers will be needed to fill the gap left by Rabada when the second match of four starts on Friday.
However South Africa react there, though, Du Plessis is adamant the 22-year-old must not let his one-match ban affect his whole-hearted fast bowling.
Rabada was described by his team-mate Temba Bavuma as "heartbroken" at letting his country down.
But Du Plessis said: "I'd never say to KG 'change the way you are'.
"It's important that he plays the way he does - I think every guy in cricket needs his instinct and personality, because that creates the best 'you'.
"For not one second must he lose that."
Rabada has made clear he is contrite, but Du Plessis added: "I'd never expect him to apologise to the team.
"For me, it's just showing what you're made of, that he wants to do desperately well for his country.
"Obviously, it's a big disappointment for us not having him [at Trent Bridge]. It's a shame, because he's a real big part of this team - and in a big Test series like this, you want to see your best players compete against each other."
Instead, South Africa may draft in all-rounder Chris Morris and another young seamer Duanne Olivier - or stick with the same balance of the team, with batsman JP Duminy vulnerable in any case because of Du Plessis' return to the middle order.
"Losing KG, do you look at playing a four-seamer attack, because you're losing quite a high-quality bowler?" the captain asked.
"That means a batsman would miss out. Obviously, that's one option.
"JP will be the first guy to say he needs to score runs for this team.
"He's desperate to do well ... but he knows at the end of the day it's about runs.
"So if someone else needs to be looked at, he'll be the first to acknowledge ... he'll always put the team interest above himself."
Either way, South Africa will be under orders to cut out the basic errors which twice reprieved England captain Joe Root early in his first-innings 190 and also included two wickets chalked off for no-balls.
"This Test match was just a lot of errors, a lot of basic mistakes that we don't normally do as a team," said Du Plessis.
"That will cost you, if you're playing against a strong team like England.
"So we've got some pretty straightforward things to focus on this week - get your basics right, and do things consistently better for longer.
"We need to put this disappointment behind us and start gearing up for what will be another very hard Test match - but certainly, we'll be up for it."
Meanwhile, South Africa coach Russell Domingo's mother has died from the injuries she suffered in a recent car crash.
Domingo left his team's tour of England during the Lord's Test after his mother's condition worsened following the accident last month.
He flew home to Port Elizabeth at the time, returning for the start of the Test series in which the tourists trail 1-0.
On Monday morning, however, Cricket South Africa announced on Twitter that she has died.
The post read: "Our deepest condolences go out to Russell Domingo and his family following the untimely passing of his mother late last night. #RIP".
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