South Africa look set to be minus Eben Etzebeth for most of June after it was confirmed the lock requires three more weeks of rehabilitation.
This means that only after the treatment can he be considered for selection to make his comeback after injuring his foot at the end of last season.
"Eben's situation is a major setback as he is been one of our best players in the last two seasons," explained coach Heyneke Meyer.
"We're continually monitoring his injury, because he really wants to play for the Springboks next month. However, he is still young and has a highly promising career ahead and his welfare is the most important to us."
Etzebeth was one of ten players who took no or little part in the field sessions at the Springbok camp in Durban, which concluded on Wednesday.
"We evaluated Eben's injury at the camp and he did not take part in any of the field sessions, as we are managing the process of his return to the field," said Springbok team doctor, Craig Roberts.
"We've been in discussion with his franchise, his rehab specialist and the foot specialist who operated on him last year. We're happy with his progress and will work closely with Western Province to ensure he gets back on the field without any risk of further aggravating the injury."
The other players who missed training sessions at the camp, were Frans Malherbe (prop), Schalk Burger (loose forward), Willem Alberts (loose forward), S'bura Sithole (centre/wing), Frans Steyn (utility back), Juan de Jongh (centre), Johan Goosen (fly-half), Bismarck du Plessis (hooker) and Duane Vermeulen (number eight).