South Africa prop Gurthro Steenkamp is facing six weeks on the sidelines after fracturing his forearm.
The 29-year-old loosehead, who was named the SA Rugby Player of the Year award in 2010, suffered the injury in the Bulls' clash with the Stormers.
And Bulls team doctor Org Strauss admitted Steenkamp will now be out of action for the next few weeks.
"Gurthro took a knock to his forearm during last week's match and x-rays on Tuesday confirmed that he fractured the same bone that kept him out of action last year," said Bulls team doctor Org Strauss.
"He will be out of action for five to six weeks."