Fast bowlers Andre Nel and Monde Zondeki have both missed out on central contracts from Cricket South Africa (CSA).
Nel, 31, is a veteran of 36 Tests but his career has often been overshadowed by disciplinary problems and he is currently suspended from domestic cricket following two separate swearing incidents.
He has not featured for the Proteas since last year's tour of England and, along with Zondeki, has been omitted from the list of 16 players handed one-year CSA deals that run from May 2009.
Left-arm paceman Lonwabo Tsotsobe, who made his one-day debut during the recent series in Australia, is the most surprising inclusion.
"He is a very committed young man and has fitted into the South African set-up very well indeed," CSA chief executive Gerald Majola said of Tsotsobe.
"He certainly proved his mettle in the final ODI against Australia, when he took 4 for 50 on debut in Perth, and bowled exceptionally well during the last powerplay which helped South Africa win the match and the series 4-1.
"Lonwabo's fast left-arm swing bowling also brings a new dimension to the attack, and he will certainly be a contender for both Tests and ODIs."
CSA national contracts: G Smith, H Amla, J Botha, M Boucher, AB de Villiers, JP Duminy, H Gibbs, P Harris, J Kallis, N McKenzie, A Morkel, M Morkel, M Ntini, A Prince, D Steyn, L Tsotsobe