Sacha Feinberg-Mngomezulu is set to miss the opening three rounds of the Rugby Nations Championship after injuring his ankle during the Stormers' 44-21 URC quarterfinal win over Cardiff on Saturday, with the Stormers confirming on Monday he will be sidelined for a period without specifying a timeline.

The 24-year-old hurt his ankle in the act of scoring a try and will not join the squad travelling to Dublin for Saturday's semifinal against Leinster.

In an Instagram post on Sunday night, Feinberg-Mngomezulu acknowledged it was his first injury in 14 months. "Frustrated, irritated, and questioning why me?" he wrote. "Another injury, another chance to come back hungry, determined, and focused. I've got a job to do, get back, and get back better than I left."

The timing compounds a growing injury crisis in the Springbok backline. Feinberg-Mngomezulu and Cobus Reinach had been pencilled in as the first-choice halfback pairing for July's home Tests against England, Scotland and Wales, but Reinach has been managing a knee injury for the past month and remains doubtful. SA Rugby also carries concerns over three further scrumhalves, while the lock stocks are stretched with Eben Etzebeth, Lood de Jager and RG Snyman all carrying knocks.

Should Feinberg-Mngomezulu's recovery extend beyond July, the implications for the four-Test series against New Zealand in August and September would be significant.