Cardiff Blues captain Andries Pretorious will not make his debut for Wales during the Six Nations after being ruled out until May because of shoulder surgery.
The 27-year-old loose forward, born in South Africa but qualified for Wales on residency grounds, was selected in his adopted country's Six Nations squad but did not feature in matches against Ireland, France and Italy.
Pretorius aggravated a shoulder injury playing for the Blues against Edinburgh earlier this month.
And a statement issued by the Blues on Tuesday said: "Following consultation with the medical team, Pretorius underwent shoulder reconstruction surgery on Friday, which went well, and the Blues No.8 is due to return to full training in May."
That ruled Pretorius out of the rest of the season, with defending Six Nations champions Wales still to play Scotland at Murrayfield on March 9 before concluding the tournament at home to England a week later.
Whether Pretorius regains full fitness in time for Wales's two-Test tour of Japan in June remains an open question.