Springbok coach Heyneke Meyer has invited 36 players to attend his first training camp of the year in Cape Town from 14 to 16 April.
The three-day camp will start on Sunday, the day after the Super Rugby derby between the Stormers and the Sharks in Cape Town.
"With minimal time to prepare for the series involving Italy, Scotland and Samoa, we've approached the franchises, in line with the IRB Regulations, to ask for their assistance with these two camps," said Meyer.
"It's important to keep continuity and it was very difficult to select only 36 players, as there are many more that are currently playing great rugby.
"There have been a number of new faces that have put up their hands this year, such as Pieter-Steph du Toit, Jan Serfontein and Robert Ebersohn, while we also have a high number of players out with injuries, but who will be available for the Tests in June.
"This group is by no means a final one for the June Tests and could still change in the coming months.
There are other players that impressed me in the last couple of weeks and if they continue to keep up their form I will look at them for the second camp."
The core of the invited group played for the Springboks last year, while Du Toit and Serfontein, two members of last year's Junior World Championship winning SA Under-20 squad, were also invited.
HandrÃ© Pollard, who also excelled for the Junior Boks in 2012, was considered for the camp, but it was decided that it would be better for him and the SA U20s' preparations if he toured with Dawie Theron's squad to Argentina.
The invited group includes a number of injured players who should be available in June. Andries Bekker, who will play club rugby in Japan at the completion of the Super Rugby season, and the injured Jaco Taute were not considered.
Three other overseas-bound Springboks, Bryan Habana, MornÃ© Steyn and JuandrÃ© Kruger, are available to play for South Africa and were invited.
Meyer and his assistant coaches have been travelling across South Africa since the start of Super Rugby, visiting franchises and sharing information with the franchise coaches and senior players.
"Last year we didn't have any time to sit with coaches at the various franchises and share ideas," said Meyer.
"They work with our top players on a daily basis and know them best, which makes their thoughts and insights very important to the national cause.
"I've been very well received and appreciated the time they gave me and the rest of the coaching team. I've learnt a lot from all of the franchises and hopefully we added some value to them as well."
Meyer's visit to the Southern Kings in Port Elizabeth was postponed on their request and will happen as soon as possible after their return from Australia.
The Kings return from their Australasian tour this weekend and were not considered for this camp, but will be in contention for the second planned training camp, at the end of May in Durban.
Players invited to the first Springbok training camp of 2013:
Forwards: Tendai Mtawarira, Jannie du Plessis, Frans Malherbe, Coenie Oosthuizen, Pat Cilliers, Adriaan Strauss, Bismarck du Plessis, Chiliboy Ralepelle, Eben Etzebeth, Flip van der Merwe, JuandrÃ© Kruger, Pieter-Steph du Toit, Franco van der Merwe, Siya Kolisi, Marcell Coetzee, Willem Alberts, Arno Botha, Duane Vermeulen, Pierre Spies, Ryan Kankowski.
Backs: Jano Vermaak, Francois Hougaard, Pat Lambie, MornÃ© Steyn, Elton Jantjies, Jean de Villiers, Frans Steyn, Juan de Jongh, Jan Serfontein, Robert Ebersohn, Bryan Habana, Lwazi Mvovo, Raymond Rhule, JP Pietersen, Bjorn Basson, Zane Kirchner.