Springbok flyhalf Sacha Feinberg-Mngomezulu suffered a serious ankle ligament injury during the Stormers' United Rugby Championship quarterfinal win over Cardiff on Saturday.
Feinberg-Mngomezulu was tackled by Cardiff's Ioan Lloyd while scoring a try in the 51st minute at DHL Stadium. Stormers director of rugby John Dobson described the injury as serious and noted that scans are pending.
The injury adds to a growing list of absences for Springboks coach Rassie Erasmus ahead of a Test series against the All Blacks. Players including RG Snyman, Kwagga Smith, Morné van den Berg and Lood de Jager are already ruled out for extended periods.
The Stormers will travel to Dublin to face Leinster in the semifinal next week, while the Bulls head to Glasgow. Dobson confirmed additional Stormers injuries to Seabelo Senatla, Ruben van Heerden and Dan du Plessis.