South African-born Wales flank Andries Pretorius has been forced into retirement by a rare auto-immune condition.
The 29-year-old's club Worcester said he has neuromyotonia (or Isaacs' Syndrome) which causes continuous muscle cramping.
'I can't perform to the standard I know is required to push myself and my team-mates without hurting myself,' he said.
Pretorius made two Test appearances for Wales on their June 2013 tour to Japan.
Photo: Huw Evans Picture Agency