Stormers loose forward Schalk Burger picked up an ankle injury in last week's 17-13 loss to the Bulls, sidelining him for up to five weeks.
The injury to Burger will subsequently rule him out of selection for the Springboks' three-match Test series against Ireland on home soil.
The 33-year-old veteran has made 86 appearances for the Boks and will be missed when head coach Allister Coetzee names his squad for his first Test series in charge of South Africa.
The Cape franchise head coach Robbie Fleck has confirmed that Burger will miss out on adding a further three caps to his name.
"Schalk is out and will miss the Bok Tests, and we hope that we will back for the Rebels game on July 2," Fleck told reporters.
"It is a big blow for him as he still has strong Springbok ambitions.
"I'm sure that he would've had a few discussions with Allister (Coetzee) this week, but for us, we want him back for the Rebels game."