Bulls medic Dr Org Strauss, said on Sunday there is a chance Du Preez has torn a calf muscle, but the extent of the injury will only be known on Monday afternoon.
Du Preez's Springbok team-mate, Wynand Olivier, hurt his back as well as his leg against John Mitchell's team and although he may miss a training session or two earlier this week, Dr Strauss is optimistic he will recover in time for the big South African derby.
The rest of the squad are all eligible for the clash against the Cheetahs and Bakkies Botha makes a welcome return to the group after serving his three week suspension.