Cape Town - The Stormers are sweating over the fitness of flyhalf Robert du Preez after he left the field against the Cheetahs in Bloemfontein on Saturday with a knee injury.
The specifics of the injury are not yet known - the Stormers are expecting to have some kind of clarity later on Monday - but a spokesperson from the union told Sport24 on Monday morning that it was "not looking good".
Du Preez, who hobbled off in visible pain in the 45th minute, is not expected to train this week.
Kurt Coleman was Du Preez's replacement and gave a good account of himself with some solid goal-kicking under pressure.
He would be the logical choice to start in the No 10 jersey against the Sharks in Cape Town this weekend, while Brandon Thompson and Jean-Luc du Plessis should come into consideration as bench cover.
Du Preez scored 23 points in the Stormers' 33-9 win over the Bulls at Newlands last weekend.