Bulls No 8 and captain Hanro Liebenberg has been ruled out for six weeks with an ankle injury.
Liebenberg sustained the injury during his team's 34-20 loss to the Hurricanes at Loftus.
SuperSport.com reports that while he won't need surgery, he will miss the Bulls' last three Super Rugby matches against the Sharks (away), Kings (home) and Stormers (home).
In some good news for the Bulls, Handré Pollard, Dries Swanepoel and Roelof Smit have all returned to training.
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