The 20-year-old Goosen slipped and fell during training on Monday and according to a report on the supersport.com website, it is a serious cruciate ligament tear, which means at least six months on the sidelines.
“It was a freak accident,” Cheetahs team manager Eugene van Wyk told supersport. “He is a bit down, there was nobody near him at the time and he slipped while kicking balls during practice.”
Goosen is due to fly back on Thursday and will immediately undergo surgery to start his rehabilitation.
The Cheetahs have won their last two matches on their Australasian tour having beaten the Highlanders 36-19 in Dunedin and the Waratahs 27-26 in Sydney last weekend.Riaan Smit is likely to come in a flyhalf for Saturday's game against the Force in Perth, with Burton Francis moving onto the bench.
Their game at NIB Stadium kicks off at 12:35 (SA time) on Saturday.