Wales will be without Josh Navidi for the rest of their Rugby World Cup campaign after the back-rower sustained a hamstring injury in the quarter-final win over France.
Warren Gatland's side secured their place in the last four with a dramatic 20-19 victory over Les Bleus, who had Sebastien Vahaamahina sent off.
Navidi had overtaken Ross Moriarty as Wales' first-choice number eight in Japan but was forced off during the first half on Sunday.
Gatland - who plans to bring in a back, rather than another forward to replace the Cardiff Blues player - has confirmed Navidi's World Cup is over.
"He'll be ruled out. He's no good," Gatland, whose side will face South Africa in the last four, told a news conference on Monday.
"We'll be looking to bring in a replacement tomorrow [Tuesday], but we've got to go through that process.
"It's disappointing for him. We'll keep him out here. It will be nice for him to stay out for the next couple of weeks.
"It's disappointing for us to have a player ruled out. In saying that, these games are so physical to have only lost one player is a real positive for us.
"We've been pretty lucky. We're trying to keep everyone as healthy as we possibly can."
Jonathan Davies missed the quarter-final due to a knee injury, but Gatland is hopeful the centre will be available for selection on Sunday.
"He was touch and go for the weekend. He's been doing rehab and recovery," Gatland said of Davies.
"Hopefully he'll be up and running for a very light session tomorrow. We'll be doing more of the rugby on Wednesday. Hopefully he's fit and available."
Gatland claimed "the best side lost" following Wales' victory over France, but the outgoing coach was satisfied with his side's resilience and strength of character.
"We're a bit disappointed about the performance. France played exceptionally well," he added. "I thought we showed some great character and got the win.
"Disappointed with a few aspects but looking forward it's about being excited about the semi-final of a World Cup."