Cardiff - Ospreys second row Alun-Wyn Jones looks set to miss the start of Wales' defence of their Six Nations title after being ruled out for up to 16 weeks with a shoulder injury.
Jones, 27, was injured towards the end of the first half of Wales's 26-12 defeat by Argentina in Cardiff last week and was then ruled out of the rest of the European autumn series.
Subsequent scans on the injury have revealed the Ospreys captain needs to undergo surgery to reconstruct his AC joint ligaments.
Jones now faces surgery later this week before facing a lengthy recovery.
Ospreys' physio Chris Towers said in a statement issued Thursday: "He is due to undergo the surgery at the end of this week, and we will be looking at a 12-16 week rehab process post-op to get him back on the field."
Now Jones will miss the rest of the Ospreys' difficult European Cup pool campaign, with games against Toulouse (twice), Leicester and Treviso to come.
And if he does indeed spend 16 weeks on the sidelines, the British and Irish Lions second row will miss the first three games of Wales' Six Nations title defence against Ireland, France and Italy.