Flankers Schalk Burger and Heinrich Brüssow were surprise inclusions in a Springbok squad for a training camp in Durban from 25 to 28 May.
The Stormers and Cheetahs tearaways were joined in the 36-man squad by veteran Bulls lock Victor Matfield.
Sharks utility back S'bura Sithole and Cheetahs wing Cornal Hendricks, the SA Sevens Player of the Year in 2013, are two of eight uncapped players in the squad.
The others are the Cheetahs duo of Lood de Jager (lock) and Teboho "Oupa" Mohoje (loose forward); Marcel van der Merwe (prop) and Jacques du Plessis (flank/lock) of the Bulls; Marnitz Boshoff (flyhalf) of the Lions and the Stormers' Damian De Allende (centre/wing).
They will join Matfield, Burger and Cheetahs flanker Brüssow - who are back in the national set up for the first time since the last Rugby World Cup in 2011 - in a training squad that is missing a number of players due to injury.
Springbok coach Heyneke Meyer said he was happy with the form of a number of the country's top players and the uncapped players who have grabbed their chance this season, as well as the re-appearance from retirement and long-term injury of Matfield and Burger.
"Victor and Schalk have been out of rugby for a long time. They've really been in great form recently and the fact that they have not been with the Boks for more than two years, has made them hungry for Test rugby yet again," he said.
"It's great to welcome them back into the Springbok fold and I know both of them can still add a lot of value to the team with the Rugby World Cup in 2015 looming.
"I'm also looking forward to working with Heinrich for the first time. He's been playing very well for the Toyota Cheetahs since returning from injury and brings a lot of experience.
"However, the message to every player in this training squad is clear - everyone must accelerate in each area from the first moment we are together as a team and that inclusion in this squad is no guarantee of selection."
Meyer said that injuries had been a concern but they had allowed other players to press their claims. A number of players in the squad are still nursing niggles or recently returned from long-term injuries.
"It looks like most of the guys are improving weekly and a few new players have put up their hands, which is good to see with the first match of the season, against the World XV in Cape Town, only a few weeks away." said Meyer.
"It's also very encouraging to see a bunch of new players emerging from Super Rugby.
"This camp will provide us with a great opportunity to work with these players before the squad for the Incoming Series is finalised. I am looking forward to work with these players for the first time.
"This is a very big year for us and the players know they will have to step up a gear, be sharp and focused from the moment we get going in Durban. We have 14 very challenging matches ahead in 2014 and it's imperative that we build on what was a good season last year.
"It's important that we start building continuity because there are just 18 matches left until the Rugby World Cup starts. But it's just as important to recognise continuous good form. We also have a number of players struggling with injury niggles or returning from injury which we have to assess."
Players based in France, England and Ireland were not considered for this camp as most of them are still playing for their respective clubs.
However, the experienced Fourie du Preez, who played for the Springboks in 2013, has been invited to the camp in Durban as he is available for the June Tests against Wales and Scotland as well as against the World XV.
The players invited to the training camp will assemble in Durban on Sunday morning and will return to their franchises on Wednesday morning.
"We have a good working relationship with our local franchises and we have to thank them, as well as Suntory in Japan, for allowing their players to attend this camp," said Meyer.
Players who were involved with the Springboks last year, but were not considered for selection because of medium to long-term injuries, are Scarra Ntubeni (foot), Chiliboy Ralepelle (knee), Frik Kirsten (neck), Pieter-Steph du Toit (knee), Franco van der Merwe (ankle), Arno Botha (knee), Pierre Spies (bicep), Louis Schreuder (hand), Pat Lambie (bicep), Gio Aplon (elbow) and Jaque Fourie, who could potentially miss the entire Test season because of an ankle injury.
South Africa training squad:
Forwards: Tendai Mtawarira (Sharks), Trevor Nyakane (Cheetahs), Marcel van der Merwe (Bulls), Jannie du Plessis (Sharks), Frans Malherbe (Stormers), Coenie Oosthuizen (Cheetahs), Bismarck du Plessis (Sharks), Adriaan Strauss (Cheetahs), Eben Etzebeth (Stormers), Lood de Jager ( Cheetahs), Victor Matfield (Bulls), Flip van der Merwe (Bulls), Heinrich Brüssow (Cheetahs), Marcell Coetzee (Sharks), Siya Kolisi (Stormers), Willem Alberts (Sharks), Jacques du Plessis (Bulls), Teboho Mohoje (Cheetahs), Duane Vermeulen (Stormers), Schalk Burger (Stormers).
Backs: Fourie du Preez (Japan), Francois Hougaard (Bulls), Johan Goosen (Cheetahs), Marnitz Boshoff (Lions), Jean de Villiers (Stormers), Damian De Allende ( Stormers), Jan Serfontein (Bulls), Juan de Jongh (Stormers), JJ Engelbrecht (Bulls), S'bura Sithole (Sharks), Frans Steyn (Sharks), Lwazi Mvovo (Sharks), Bjorn Basson (Bulls), JP Pietersen (Sharks), Cornal Hendricks (Cheetahs), Willie le Roux (Cheetahs).