South Africa second-row Eben Etzebeth is set to be ruled out for six months due to surgery on his right ankle.
The 22-year-old, who already has 23 caps, suffered the injury in the Springboks' win over France last Saturday.
Etzebeth departed early, replaced by Bakkies Botha, before re-emerging before half-time on the sidelines with his foot in a protective boot.
Surgery on Monday will force Etzebeth out of action until next May, making him miss out on the beginning of next year's Super Rugby tournament with the Stormers.
Should he be out for six months as expected, Etzebeth will miss matches against the Lions, Hurricanes, Crusaders, Chiefs, Brumbies, Reds, Waratahs and Cheetahs.
"Just for those who would like to know, going for operation on Monday. +-6 months out of action. Have a great day people!" Etzebeth wrote in a tweet on Thursday.
Etzebeth was one of five players nominated for the IRB Player of the Year Award earlier this month.