Springboks lock Eben Etzebeth will be out for at least four months after he undergoes surgery next week for a foot injury.
The Cape Town-based Stormers say their second-rower will have an operation on Monday and then be sidelined for 16-18 weeks.
The 22-year-old Etzebeth is unlikely to return before April, ruling him out of the opening part of next year's Super Rugby season, which starts on February 15.
Etzebeth was hurt in No 2-ranked South Africa's season-ending 19-10 win over France in Paris on Saturday.
The 6-foot-8 (2.04-metre) forward has also been nominated for this year's IRB player of the year award alongside New Zealand pair Kieran Read and Ben Smith, Wales fullback Leigh Halfpenny and Italy No.8 Sergio Parisse.