Franco van der Merwe.

Franco van der Merwe. Photo: Getty Images

South Africa lock Franco van der Merwe has been ruled out for six months after undergoing ankle surgery on Monday, adding to a growing list of Springboks likely to miss this year's Rugby Championship.

Van der Merwe, 31, sustained a severe ankle injury on Saturday during the Lions' 23-20 Super Rugby victory over Queensland Reds at Ellis Park and will be out until September, his club said in statement on Tuesday.

The Rugby Championship, featuring South Africa, Argentina, Australia and New Zealand, runs from Aug. 16 to Oct. 4.

Van der Merwe's injury comes a day after Sharks flyhalf Pat Lambie was told he will to miss the remainder of the Super Rugby season with a torn bicep tendon.

Other Springboks currently out of action include Arno Botha, Bakkies Botha, Pieter-Steph du Toit, Eben Etzebeth, Bryan Habana, Coenie Oosthuizen and Pierre Spies. 

Reuters