Keegan Petersen, the Knights' No. 3, has been called up to the Test squad as an injury replacement for Aiden Markram, who was ruled out of the series with a fractured finger. Petersen scored 111 against England in the warm-up game in Benoni last week and was the leading run-scorer in the four-day franchise series last summer, with 923 runs to his name at an average of 61.53.

Petersen's addition to the group gives South Africa another option as they seek to find room for Rassie van der Dussen and Temba Bavuma, who is likely to be fit for the New Year's Test, and meet their transformation target. South Africa's XI at SuperSport Park includes only one black African player (Kagiso Rabada) and three players of colour (Zubayr Hamza, Vernon Philander and Keshav Maharaj), which is two short of the target of six players of colour of which two must be black Africans. Although the target is only calculated on average over a season, South Africa will want to avoid falling short of it repeatedly as it would affect overall calculations.

That means that South Africa may look to get closer to the transformation target in Cape Town, by selecting from Bavuma, who is recovering from a hip injury, Andile Phehlukwayo, Beuran Hendricks, Dane Paterson and Keegan Petersen - all of whom are players of colour. For Bavuma to fit into his regular spot at No. 5, van der Dussen may need to be moved up the order into Markram's opening spot.

Van der Dussen has experience opening the batting at first-class level but, recently, he has played more in the middle order. If both van der Dussen and Bavuma play in the middle order, spare opener Pieter Malan could be considered at the top, but that would have to come at the expense of an allrounder, most likely Dwaine Pretorius. However, Pretorius has put in a decent performance at SuperSport Park which could help him retain his place in Cape Town.

Petersen's inclusion could also be interpreted as competition for Hamza, who is only three Tests into his career and has shown sound technique. A CSA statement said Petersen's call-up was a "bid to reward excellence" and give the 26-year-old experience of being around the national side. The squad also includes the uncapped reserve wicketkeeper-batsman Rudi Second, who fielded in Markram's place at short leg in England's second innings.

Firdose Moonda is ESPNcricinfo's South Africa correspondent