Ospreys flanker Justin Tipuric has been ruled out of Wales’s summer tour to New Zealand after suffering concussion during the Six Nations against Italy last month.
The Ospreys said that 26-year-old Tipuric would undergo "a prolonged three-month period of recovery".
He went off early during the 67-17 Wales victory over Italy, which secured second place in the Six Nations behind Grand Slam champions England.
Ospreys medical performance manager Chris Towers said: "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."
Tipuric's Ospreys and Wales team-mate Paul James could also be sidelined for the three-Test trip, as he faces a lay-off of six to 10 weeks following eye surgery.
The duo are among four Ospreys players to be ruled out for the rest of the season, with the club also announcing JJ Engelbrecht and Ma'afu Fia will miss the remainder of the campaign.
Engelbrecht requires surgery on his ankle while Fia is recovering from an operation on his toe.
Regarding prop James, meanwhile, Towers added: "Following eye surgery, Paul is scheduled for a review with the specialist at the end of this week to get a fuller picture of the recovery process.
"However, we know that he is likely to be out of rugby for a period of six to 10 weeks."