Cardiff Blues have wished Matthew Rees "a speedy recovery" and said they "look forward to seeing him back in action in the future", after it was announced he will have testicular surgery.
The 32-year-old hooker joined the club from the Scarlets in the summer, and was made Blues captain.
He led the region to a shock victory over Heineken Cup holders Toulon at the weekend.
The Blues say he will miss Friday's game away at Ulster, as he takes an "enforced spell away from rugby."
Rees has won 58 caps for Wales, and played for the Lions in South Africa in 2009.