Wales will be without injured prop Gethin Jenkins for their opening World Cup pool game against South Africa.
The loose-head has not played any rugby since injuring his calf in January.
Injury has already ruled out Jenkins' fellow British and Irish Lions front-row Matthew Rees from the whole World Cup, as the captain needs neck surgery.
"We've had him re-scanned and there's some damage in the calf and... he's seeing a specialist this week," said Wales coach Warren Gatland.
"That probabably rules him out of consideration for that South African game, the first game of the tour if he's selected.
"It's a concern for us, he's as frustrated as anyone; he's worked really hard as all the players have in the pre-season and he just hasn't been able to get himself right.
Jenkins is one of the best loose-heads in the world but the Cardiff Blue last played for Wales in the 25-37 defeat to New Zealand at the end of November.
"He's done a lot of 'rehabbing' that calf and trying to get it right," Gatland added.
"But we know what a quality player he is, so the hope is he will show signs of improvement and that maybe we may be able to consider him for other games in the World Cup."
Wales have already lost back Morgan Stoddart to a broken leg, suffered in the defeat to England at Twickenham two weeks ago.
Centre Gavin Henson is also out of the start of the World Cup with the wrist injury he suffered in last weekend's win over England in the return test in Cardiff.
Gatland will be hoping that this Saturday's final World Cup warm-up against Argentina in Cardiff will not produce any more players for the casualty list.
"You don't want to go to the World Cup with too many players that aren't 100% fit," Gatland said.
"There is a lot of depth in the forwards at the moment and part of that criteria is picking players that are fit. We might have the luxury of carrying one, maybe two.
"I've spoken to the physios and they're confident that three weeks before the first game against South Africa that they should have him [Jenkins] right by then, and it's maybe the second game in the World Cup that he might be available."