Leigh Halfpenny has been ruled out of the Wales side for their Test against South Africa in Cardiff on Saturday after suffering concussion against Australia.
The Scarlets full-back was on the receiving end of a challenge by Australia centre Samu Kerevi when Wales beat the Wallabies on November 10.
Wales assistant coach Rob Howley confirmed on Tuesday that Halfpenny would miss the Springboks game.
Wales have options at number 15, with Liam Williams, who started on the wing and scored two tries against Tonga last weekend, one candidate.
Fly-half Gareth Anscombe could be another contender as Wales look to complete a first sweep of autumn Test victories.
They are also chasing a ninth successive win against all opponents, which would equal their longest unbeaten run since 1999.
Wales coach Warren Gatland is due to announce his startling line-up on Thursday.
"Leigh is out," said Howley. "He did some training on Saturday morning, and he was still feeling a little bit light-headed.
"It is just a commonsense approach, really. A player's welfare comes first. He unfortunately misses out this weekend."
Halfpenny is the first-choice goal-kicker, with more than 700 points for his country, but Wales have other strong options in that area, able to call on Anscombe, Dan Biggar and Rhys Patchell.
Howley confirmed that wing George North is back in training after suffering a dead leg during the Wallabies clash.
"I'm glad to say George North is back in full training," Howley added. "He trained this morning and is available for selection."