Stormers and South Africa flanker Schalk Burger will miss at least the first three weeks of the Super Rugby season because of a calf strain.
Burger, a Rugby World Cup winner with the Springboks six years ago, sustained a knee injury in the opening round of the 2012 championship and missed the entire season.
He picked up the strain during pre-season preparations and coach Allister Coetzee said the loose forward would not be considered for games against the Bulls and Sharks (both away) and title-holders, the Chiefs (home).
"If we were playing a semi-final, we may have risked Schalk," Coetzee told reporters in Cape Town. "But at this stage of the season I do not want to risk him."
Injured centre Juan de Jongh and lock Eben Etzebeth also miss the clash with the Bulls in Pretoria and centre Jean de Villiers continues as stand-in skipper for Burger.