Bulls tighthead prop Frik Kirsten has been advised by doctors retire due to a serious neck injury.
The 25-year-old has been sidelined since March after sustaining the injury in a Super Rugby match against the Lions at Loftus Versfeld.
Kirsten's dad, Barend, said it's uncertain if his son will ever play rugby again.
"Fusion surgery will have to be 100% successful for him to stand any chance of playing again," he told the Beeld website.
Kirsten will undergo a follow-up scan in October before deciding on his future in the game.