Bulls coach Frans Ludeke has called in two replacements for his side's last match of their Australasian tour against the Brumbies on Saturday.
Lock Wilhelm Steenkamp and loose forward Jean Cook will leave for Canberra to replace Flip van der Merwe and Grant Hattingh respectively.
Van der Merwe has not recovered from a chest muscle strain while a scan revealed a broken thumb for Hattingh.
The experienced Steenkamp has 52 Super Rugby caps under his belt, while Cook debuted for the Bulls against the Western Force earlier in the season, scoring a try in the process.
A final fitness call on Bjorn Basson and Deon Stegmann will be made on Wednesday. Basson still has trouble with an ankle and Stegmann will have to prove that he is over his hamstring strain.