Wales back-rower Justin Tipuric will miss June's tour of New Zealand as he requires a prolonged period of recovery from concussion.
The Ospreys forward was injured playing against Italy in the Six Nations last month and will take a three-month break from the game.
Tipuric subsequently misses the rest of the Pro12 season, while he is also unavailable for Wales coach Warren Gatland when they take on the All Blacks in three tests in June.
Ospreys' medical performance manager Chris Towers told the club's official website: "Justin is recovering well following the concussion suffered playing for Wales against Italy three weeks ago, but in the light of his symptoms the specialist advice is that it is in his best interests to take his time returning.
"A prolonged three-month period of recovery rules him out of the rest of the season for the Ospreys and the Wales tour to New Zealand. The focus for Justin will be on getting healthy and fit, ready for pre-season."
It is another blow for Wales as reports emerged in France on Monday that Toulon full-back Leigh Halfpenny's participation in the New Zealand tour is in doubt as he requires further surgery after rupturing his anterior cruciate ligament before the Rugby World Cup last year.
South Africa international JJ Engelbrecht will also miss Ospreys' run in as he requires ankle surgery on an injury sustained against Connacht in March.
Towers added: "Despite a period of rehab following the ankle injury he sustained against Connacht, it was felt that he wasn't recovering as would be expected.
"The best long-term option for him was to have surgery to stabilise the ankle, ruling him out for the rest of the season."