Dean Greyling and Marcel van der Merwe will miss the Bulls Super Rugby opener against the Stormers, as will Akona Ndungane.
The two props will be out for a fortnight and three weeks respectively, with Greyling suffering from a foot injury, while Van der Merwe has a hamstring problem.
Ndungane should be out for just one week as he recovers from a calf injury.
To complicate matters a bit more for Bulls coach Frans Ludeke, winger Travis Ismaiel has been ruled out for selection due to a hamstring strain and prop Hencus van Wyk (foot) will only return to training at the end of the month.
All of Basil Short (pectoral), Jason Jenkins (quad), Trevor Nyakane (contusion), Nicolaas Janse van Rensburg (hamstring), Deon Stegmann (hip) and Jesse Kriel (neck) completed a full training session today.
Flip van der Merwe (pectoral, mid-April), Bandise Maku (pectoral, 4-6 months) and Pierre Schoeman (ACL, 15 July) remain on the long-term injury list.