South Africa captain Jean de Villiers needs reconstructive knee surgery and faces a race against time to be fit for next year's World Cup.
The 33-year-old centre twisted his knee, dislocated his knee cap and damaged ligaments in the 12-6 defeat by Wales in Cardiff on Saturday.
Springboks medical staff estimate he will be out of action for at least eight months.
The 2015 World Cup in England and Wales starts on 18 September.
Springboks team doctor Craig Roberts said in a statement from South Africa Rugby Union: "We are currently consulting with the best specialists in South Africa to determine the best way to approach the surgery as there are potentially a few options available.
"It's imperative that the best course of action is decided on so that Jean can start recovery and rehabilitation as soon as possible to give him the best chance to be fit for the World Cup."
De Villiers, who has 106 caps, left the field on a stretcher at the Millennium Stadium after his knee bent awkwardly underneath him in a ruck early in the second half.
He has suffered knee problems in the past, causing him to miss last summer's Tests against Wales and Scotland.
De Villiers also has an unfortunate history of injuries around World Cups, missing the entire 2003 edition and then tearing his left biceps in South Africa's first game of the 2007 tournament, ruling him out of the rest of the Boks' title-winning campaign.