The Bulls will be without Springbok centre Jesse Kriel for the next six to eight weeks as he prepares for surgery on his injured ankle this week.
Kriel limped out of the Pretoria-based side’s 24-23 defeat to the Stormers at Newlands on Saturday, and it has been confirmed he will now go under the knife.
"Jesse Kriel has torn a ligament in his ankle and will undergo surgery later this week. He is expected to be out for a period of six to eight weeks," Bulls team doctor Herman Rossouw told the team website thebulls.co.za on Tuesday.
Wings Divan Rossouw and Jade Stighling will also miss Saturday’s home fixture against the New South Wales Waratahs after they left the field with concussion at the weekend and have not been passed fit to play.
Better news for coach Pote Human is that centre Burger Odendaal will be eligible after being cleared by a specialist after sustaining an eye injury against the Stormers.
The Bulls are second in the South Africa Conference, two points behind the Sharks but with a game in hand.
Ireland may face the Springboks at the World Cup should both sides qualify from their respective pools.
Meanwhile, Heineken Champions Cup finalists Saracens have signed England age-grade tighthead prop Josh Ibuanokpe from Harlequins.
Ibuanokpe, 23, made his senior Quins debut in last season's Anglo-Welsh Cup and has made his first Gallagher Premiership appearance in the current campaign.
"Saracens have a history of developing young players and I'm excited to see how far my game can develop with them," Ibuanokpe told the club website.
"I know a few of the players at the club and they've spoken about the tight-knit nature of the squad."