Wales flanker Josh Navidi will miss the remainder of the Rugby World Cup with a hamstring injury, according to head coach Warren Gatland.
Navidi, 28, was substituted in the first half of the 20-19 quarterfinal victory against France on Sunday.
"He'll be ruled out," Gatland told a news conference on Monday. "He's no good. "It's disappointing for him. We'll keep him out here.
"In saying that, these games are so physical to have only lost one player is a real positive for us."
Winger Owen Lane has been called up into the Wales squad as an injury replacement, the Welsh Rugby Union said on Tuesday.
Lane can play on the wing or in the centres, where Wales have a number of injury concerns after Jonathan Davies missed the France match with a knee injury and with Hadleigh Parkes nursing shoulder and finger problems.
Wales defence coach Shaun Edwards said Lane's infectious personality would also be a bonus for a road-weary squad.
"Owen is a very buoyant character," Edwards told reporters at a news conference. "Sometimes when you're away from home for a long time, you need very positive people.
Lane, 21, made his test debut against Ireland in Cardiff in late August, scoring Wales's first try in a 22-17 loss. He will arrive in Japan on Tuesday.
"We were very impressed with him in the summer. He's obviously a very good player and has huge potential going forward," Edwards added.
Navidi has been Wales' preferred option at No. 8 following the injury that ruled Taulupe Faletau out of the competition.
Gatland is also hopeful centre Jonathan Davies could return to action after missing the win against France.
"He's been doing rehab and recovery," he added. "Hopefully he'll be up and running for a very light session tomorrow. Hopefully he's fit and available."
Wales will face South Africa in the semifinals on Sunday as they attempt to reach the World Cup final for the first time in their history.
Information from Reuters was used in this report.