South Africa paceman Lungi Ngidi has been ruled out of the second and final Test against New Zealand with a back strain, the team said on Thursday.
The 25-year-old missed the first Test, which saw South Africa thrashed by an innings and 276 runs in Christchurch over the weekend.
"Because he hasn't been able to bowl last week, I don't think his bowling loads are up to the standard of preparing for Test matches," captain Dean Elgar told reporters.
"He hasn't been training with us, he's only been bowling off a short run-up, which has been a bit of a setback for us.
"We know Lungi's been a key figure within our bowling lineup. So it's a bit disappointing that he's in the situation that he's in now."
South Africa went with the four-prong pace attack of Kagiso Rabada, Marco Jansen, Duanne Olivier and Glenton Stuurman in the first Test but the strategy misfired, with New Zealand's batsmen racking up 482 to set a platform for victory.
Stuurman had a torrid debut, conceding 1-124 at more than four runs an over, and could be replaced by two-Test quick Lutho Sipamla, or Keshav Maharaj if the Proteas opt for a specialist spinner.
With multiple players out of form, Elgar said selection changes were a "big possibility" while declining to name any.
"I'm sure there are guys who are a little bit low in confidence, especially from a batting point of view," he said of a team that scored just 95 and 111 in the series-opener, their second-worst Test defeat ever.
New Zealand eye top spot and a first series win over South Africa
New Zealand will look to complete a maiden Test series win over South Africa and savour rare air at the top of the world rankings with victory over the ailing tourists in the second and final match starting on Friday in Christchurch.
Though lacking injured captain Kane Williamson and pace spearhead Trent Boult, the World Test champions were unstoppable in the first meeting in Christchurch, subjecting South Africa to their second-worst Test defeat ever.
New Zealand have suffered 90 years of frustration against the Proteas since being swept 2-0 at home in 1931/32, but a draw at Hagley Oval would be enough to end the winless streak.
It would also complete New Zealand's set of series wins over Test-playing nations and put them top of the world Test rankings.
Stand-in captain Tom Latham said his team were focused more on what a win could do for the defence of their World Test Championship than the chance to erase an historical anomaly.
"On the whole for us it's about the World Test Championship and you need as many points as possible," he told reporters on the eve of the second Test on Thursday.
"Points at home are really vital.
"Nowadays in international cricket, it's so hard to win away from home."
With Boult still on paternity leave, New Zealand will be tempted to stick with the four-prong pace attack that bowled South Africa out for 95 and 111 in the series-opener.
Colin de Grandhomme's back-up pace was scarcely needed in that match, but Latham said selectors would decide on whether to include an all-rounder after looking at the pitch in the morning.
South Africa's tour has seemed ill-fated from day one, having to spend 10 days in COVID-19 quarantine upon arrival and then losing paceman Lungi Ngidi to injury.
None of their batsmen made a half-century in the first Test and struggling number three Aiden Markram, who scored 15 and two, looks set to be dropped.
Pace bowler Glenton Stuurman may also make way after a torrid debut in which he conceded 1-124. He could be replaced by two-Test quick Lutho Sipamla, or Keshav Maharaj if selectors opt for a specialist spinner.
Captain Dean Elgar hinted strongly at selection changes and demanded more from his team in all facets of the game.
"It is a little bit frustrating and disappointing that we haven't fulfilled our ability," he told reporters.
"Guys know what's expected of each individual going into the second Test."
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