Springbok number eight Duane Vermeulen has suffered a knee injury while playing for his club Toulon and has been withdrawn from the Test squad.
South Africa face Argentina next week in their first Rugby Championship match of the year.
The Boks' opening game of the 2016 campaign takes place next Saturday at the Mbombela Stadium in Mpumalanga.
Vermeulen underwent an MRI scan on Friday evening after playing for his club and he will in all likelihood have surgery next week to repair damages caused by the recurring injury to his right knee.
The Springbok management has confirmed that for now, no replacement will be called up as they feel the squad currently has sufficient cover amongst the loose forwards for the first Test against Argentina. They will assess the situation thereafter.
Meanwhile, the Springbok squad reassembles on Sunday in Johannesburg to resume with their preparations for the Pumas encounter.
Their overseas-based players as well as two Springbok Sevens Olympians will join the Bok squad in Johannesburg, from where they will travel to Nelspruit.