Munster lock RG Snyman has ruptured his anterior cruciate ligament for the second time in as many seasons since joining the Irish province for the 2020/21 season from Honda Heat.
Snyman left the field at Parc y Scarlets nine minutes after coming on as a substitute with an injury that has been confirmed to be another ACL rupture.
The 26-year-old made his fourth appearance for the Stags at the weekend and his third in as many games after returning from his first ACL injury.
The South African lasted only seven minutes on his debut for the club before suffering an injury that ruled him out for the rest of the season.
He has played for only 54 minutes in the famous red shirt and will spend a lengthy period on the sidelines before he can pass the hour mark.
Snyman scored his first try for Munster last week against the DHL Stormers at Thomond Park in front of fans.
The World Cup-winning Springbok will meet with the specialist next to discuss surgery and management.
Commenting on the injury blow, Munster Rugby Head Coach Johann van Graan said: “We are all hugely disappointed for RG.
“After doing everything that was asked of him and working so hard to get back into great shape everyone feels for him right now.
“While this is a setback, we know RG is young and resilient given everything he has gone through in the last year so there is a strong sense of perspective here.
“We have seen what other world-class players have done in this position before and they have come back to reach the successful heights of their careers and I would expect no different for someone of RG’s class and standing.”
RG commented on the news on his Instagram story, stating “Here I go again #Round2Fight.”
