South Africa v England, 4th Test, Centurion January 19, 2016

De Kock to have fitness test, Steyn out

Quinton de Kock missed the third Test after injuring his knee the day before © Gallo Images

Quinton de Kock will undergo a final fitness test on Wednesday to asses whether he is able to return as wicketkeeper at Centurion. South Africa have also confirmed that Dale Steyn will not play and released Stiaan van Zyl from the 17-man squad announced on Tuesday - increasing the likelihood that 33-year-old Lions opener Stephen Cook will make his Test debut.

De Kock missed the third Test in Johannesburg after hurting his knee while at home the day before, forcing Dane Vilas to fly up from Port Elizabeth on the morning of the game. Vilas was not, however, retained in the squad for Centurion. Steyn was included but, as revealed by ESPNcricinfo, was not expected to play as he continues to recover from a shoulder problem.

Van Zyl had been under pressure after scoring just 69 runs in five innings as South Africa conceded the series to England after three Tests. He also struggled as an opener on the tour of India but South Africa resolved to give him a chance in home conditions.

With van Zyl now discarded, Cook appears to be in line to replace him. Kagiso Rabada, who plays under Cook for the Lions, backed him to make the step up after several seasons of heavy run-scoring at domestic level.

"Stephen Cook was the leading run-scorer last year, he was also the captain of the team," Rabada said. "He played against England representing South Africa A and he has done well there too. So he has proved himself even more. I am very happy for him . He was waited a long time and I think he deserves this."

Rilee Rossouw, a No. 3 batsmen who has asked to open the batting for his franchise, the Knights, is still part of the squad and could be in competition with Cook for the opening berth. The middle order will depend on de Kock's fitness and there remains the possibility de Villiers will take the gloves if the selectors also want to find a way to get JP Duminy into the playing XI. If Duminy is to displace another batsman, Faf du Plessis is most at risk following patches of poor form.

South Africa's bowling choices remain between three seamers and a spinner or four seamers, with the former more likely on what is not expected to be as sporting a pitch as the Wanderers was. With Steyn ruled out, South Africa will choose between Morne Morkel, Chris Morris, Kagiso Rabada, Hardus Viljoen and Kyle Abbott. The early suggestion is that Abbott could find his way back in at the expense of one of Viljoen or Morris.

Firdose Moonda is ESPNcricinfo's South Africa correspondent