Bulls scrum-half Piet van Zyl has been ruled out of the Pretoria-based franchise's match with the Western Force in Perth on Saturday due to injury.
Van Zyl left the field in the 19-12 loss to the Waratahs in Sydney with a knee injury last weekend and will be out of action for two weeks, Bulls team doctor, Org Strauss, said on Monday.
Good news is that both Akona Ndungane (knee) and Jurgen Visser (foot) have been declared fit to face the Force.
Ndungane's availability will result in Francois Hougaard moving back to scrum-half.
The Bulls are also awaiting the result of captain Flip van der Merwe's citing - for allegedly striking Waratahs prop Paddy Ryan - as this will determine his availability for the match.