Sharks winger JP Pietersen is facing surgery after he damaged his knee in the victory over Western Force on Saturday.
The South Africa international had to be helped from the field in Perth and will now return home to have operation to repair his cartilage.
"He has a meniscus tear," coach John Plumtree told the club's official site.
"He's returning home and will probably be operated on Tuesday.
"Hopefully it won't be as bad as it sounds, and we won't know how long he'll be out until after the operation.
"We're looking to get Mark Richards over at this stage, he's with the SA Sevens in Cape Town. Hopefully he'll arrive later in week."
Sharks flankers Jacques Botes and Willem Alberts and winger Odwa Ndungane all suffered knocks in the 39-12 win.
However the trio are expected to be fit for Friday's clash with the Rebels.