Nayacalevu, who led his country at the 2023 World Cup in France, has left English Premiership club Sale Sharks with immediate effect.
Watkin suffered a severe knee injury during Wales’ Six Nations opener against France in Paris last month, and he is not expected to play again this season.
“It is not often a player of Waisea’s calibre becomes available in-season,” said Ospreys head coach Mark Jones. “He brings a wealth of exper犀利士
ience and leadership credentials with him.
“We feel Waisea can make an instant impact and be a real difference-maker for us in Owen’s absence, and stands us in good stead in a season where we still have a lot to play for.”
Nayacalevu, 34, signed a one-year deal with Sale before the current season, but failed to secure a regular first-team place at the northwest club.
“Unfortunately, we haven’t seen the best of him in a Sharks shirt, but he is a great guy, a brilliant player, and everyone at Sale wishes him all the best for the future,” Sale rugby director Alex Sanderson told the club’s website.
© 2025 AFP