Duanne Olivier and Chris Morris have been added to the South Africa squad for the remaining two Tests against Australia.
Fast bowler Olivier got the nod over Dale Steyn, who has yet to play a competitive match since January due to a heel injury, while all-rounder Morris is also included after impressing in domestic cricket.
South Africa were forced to replenish their pace attack with spearhead Kagiso Rabada provisionally suspended for the remainder of the series after accumulating eight demerit points over a two-year period.
Rabada is named in the squad as he has appealed the verdict – his hearing will be held on Monday – but Olivier's inclusion suggests Cricket South Africa (CSA) are not optimistic of a positive outcome.
CSA National Selection Panel Convener Linda Zondi said: "Circumstances have forced us to name a large squad at this stage so that we can cover all possible options.
"Once we have finalised our playing XI we will release players to their franchises for the final round of the Sunfoil Series.
"We have retained the 15 players who produced an excellent performance to level the Test Series in Port Elizabeth.
"Olivier was the pick of our bowlers for South Africa A in their tour match against Australia while Morris has been in excellent form in domestic cricket, taking four wickets in an innings and making more than 150 runs, including a century, for the Multiply Titans in the Sunfoil Series against the log-leading Warriors."
The series with Australia has been marked by on and off-field clashes and is tied at 1-1 after the Proteas won the second game in Port Elizabeth by six wickets last week.
South Africa squad for the third and fourth Tests:
Faf du Plessis (captain), Hashim Amla, Temba Bavuma, Quinton de Kock, Theunis de Bruyn, AB de Villiers, Dean Elgar, Heinrich Klaasen, Keshav Maharaj, Aiden Markram, Morne Morkel, Chris Morris, Wiaan Mulder, Lungisani Ngidi, Duanne Olivier, Vernon Philander, Kagiso Rabada.