One of them is likely to fill the void left by the retirement of Jacques Kallis.
Durban: Allrounders Ryan McLaren and Wayne Parnell were named in South Africa's 15-man squad on Wednesday for the three-match Test series against Australia starting on February 12.
One of them is likely to fill the void left by the retirement of Jacques Kallis, who quit the five-day game ahead of the Boxing Day victory over India in Durban last month.
The other may take the place of leg-spinner Imran Tahir, who has been dropped from the squad, leaving Robin Peterson as the only front-line spinner, with JP Duminy available as a sixth bowler.
Kallis' retirement has left the world number one team needing to fill the number four batting position and fourth bowler slot.
McLaren and Parnell have been earmarked as the most likely contenders, though they would come in to bat at seven with those above them moving up a place.
Both all-rounders made their debut in the same Test against England at The Wanderers in 2010 - a match that the Proteas won by an innings and 74 runs.
Parnell went on to play in South Africa's next two Test matches in India and since then both players have been involved in several of South Africa's Test squads abroad without playing.
"We want to stay constant to the brand of cricket we have played over the last few years that has brought us such success," Cricket South Africa (CSA) selection convener Andrew Hudson said in a statement.
"I believe that this squad covers all possible options we may wish to exercise as well as the conditions we are likely to encounter."
CSA have also announced that Cape Cobras left-arm seamer Beuran Hendricks and Warriors off-break bowler Simon Harmer will train with the squad. Hendricks will give the batsmen an opportunity to practise for their duel with Mitchell Johnson, while Harmer will help them play Nathan Lyon better.
"They are both highly talented cricketers who will benefit from being introduced to the Proteas environment. They also possess individual skills that will assist the team with their preparation for the Australian attack we are likely to face," Hudson said.
Australia will play three Tests and three Twenty20 matches in South Africa.
Squad: Graeme Smith (captain), Hashim Amla, AB de Villiers, JP Duminy, Faf du Plessis, Dean Elgar, Rory Kleinveldt, Ryan McLaren, Morne Morkel, Wayne Parnell, Alviro Petersen, Robin Peterson, Vernon Philander, Dale Steyn, Thami Tsolekile.