AB de Villiers and Quinton de Kock are expected to be fit for the start of South Africa's Test series against Australia from March 1, but doubts remain on whether captain Faf du Plessis and middle-order batsman Temba Bavuma will be ready.

While de Villiers and de Kock are recovering from knee and wrist injuries respectively, du Plessis and Bavuma are nursing broken fingers. South Africa team manager Mohammed Moosajee told ESPNcricinfo that a call on their availability will only be taken as the series draws closer. Dale Steyn, who is recovering from a heel injury, is not likely to be up for selection until at least the third Test in Cape Town on March 22.

"We've obviously had a lot of senior guys out injured and it's had an effect," Moosajee said. "But we are sure AB and Quinton will be ready for the first Test and we are hopeful Faf will be. When he was diagnosed [on February 2] we knew he would require four to six weeks recovery time, which takes us, at the earliest, to the first week in March. So we have to take it on a week-by-week basis and see how he is progressing. The same with Temba, though he might be out for a week more than Faf."

Du Plessis' availability is crucial not only because he is the captain but because South Africa desperately need bulk in their batting. The evidence of the limited-overs series against India aside, their new strategy of playing six specialist batsmen with the out-of-form de Kock at No. 6 means that du Plessis' runs will be as important as his leadership.

He also has a strong record and a fiery history against Australia, with an average of 59.14, a defiant century on debut in Adelaide, and a starring role in the series win in 2016, partly coloured with controversy. Du Plessis was infamously involved in the "mintgate" saga in which he was fined for ball tampering after shining the ball with saliva that had come into contact with a mint in his mouth. He will doubtless be itching to meet Australia again.

AB de Villiers strikes an elegant pose AFP

With de Villiers and de Kock fit, Bavuma's return is less necessary right now as he would likely only be among the reserves. Theunis de Bruyn, the other back-up batsmen who has been around the squad, may even have inched ahead of Bavuma with scores of 190 and 83 in two of his last three first-class innings.

As for Steyn, his wait to become South Africa's all-time leading Test wicket-taker will grow even longer. He has 419 scalps and is only three away from overtaking Shaun Pollock, but he needs to prove his fitness first. Steyn broke down during the New Year's Test against India - his first since November 2016 - and will likely have to play some first-class cricket before being reconsidered for the Test squad. He will either take part in the round of domestic fixtures that starts on the same day as the Test series or those in the following week.

South Africa's selectors are expected to name the squad later this week and it could be without allrounder Andile Phehlukwayo, who failed to impress in the only Test he played against India. But exactly where South Africa will look for new squad members is uncertain. Currently, Vaughn van Jaarsveld tops the first-class run charts, followed by Pieter Malan and Rassie van der Dussen, while Kolpak spinner Simon Harmer is top of the wicket-takers' list, which is dominated by slower bowlers. Legspinner Shaun von Berg and left-arm spinner Senuran Muthusamy are in second and third place with allrounders scant on the circuit.