The scrumhalf, who came into the starting lineup on the Australasian tour – shifting Francois Hougaard to the wing, injured his knee on tour and requires another week of rest.
The Bulls return home after a poor tour that emulates both the Cheetahs and the Stormers foray overseas – winning no games.
It could be expected that Hougaard will remain his preferred No. 9 jersey with Van Zyl’s injury.
Werner Kruger, who left the field in their last tour match against the Force, will train on Wednesday only.
This is in order for his back injury to recover.
Meanwhile, captain Flip van der Merwe has to see out the remainder of his suspension after striking Waratahs prop Paddy Ryan.
Van der Merwe will be back in contention for selection when the Bulls host the Stormers the following week