Dry, who played in his 63rd tournament last weekend, suffered major ligament damage in South Africa’s quarter-final victory over Fiji at the Cape Town Sevens tournament on Sunday.
Springbok Sevens team doctor, Leigh Gordon, said Dry will be out for at least six months. He will undergo surgery on Friday.
“Chris will be operated on in Cape Town and will not be able to play for between six to nine months, which means he will miss the remainder of the series,” Gordon said.
She also confirmed that Siviwe Soyizwapi, who replaced Dry for the last two matches of the tournament, suffered a knee injury.
“He should be able to return to play in about six weeks’ time,” Gordon said.
A number of Blitzboks picked up knocks in Cape Town but, according to Gordon, none of the injuries were too serious.
“Cecil Africa tweaked his knee and Seabelo Senatla has a soft tissue injury to his shoulder, but both will, along with the rest of the squad, be fit to train once the squad re-assembles in Stellenbosch early in January,” said Gordon.
Dylan Sage, who missed the first two tournaments of the 2017/18 World Rugby Sevens Series because of a back injury, will join the squad in full training in January.
The next tournament in the series is the Sydney Sevens, to be played from 26-28 January.