According to supersport.com, the former SA under-20 captain suffered a second hamstring injury in three weeks.
Botha was impressive when he came on off the bench in his side's 42-31 win over the Sharks at Loftus Versfeld on Saturday. He also missed the Bulls' clash against the Cheetahs two weeks ago after tweaking his hamstring in the opening round against Griquas on August 10.
The 20-year-old is likely to be out for one week and seems to be the only casualty from the Sharks game.
Centre Jan Serfontein and prop Frik Kirsten, who withdrew from the bench just before the Sharks clash due to flu, have recovered and can be considered for selection.
Springok winger Bjorn Basson is expected to return to action in two weeks’ time after undergoing an emergency operation to fix a perforated small intestine, while Chiliboy Ralepelle (six weeks) and Pierre Spies (ten weeks) are long term casualties.
The Bulls are currently in fourth spot on the overall log with eight points, although they're only one point behind the table-topping Golden Lions.
Their clash against WP at Newlands kicks off at 19:10 on Saturday.