Jonathan Davies is in a race to be fit for the Rugby World Cup quarter-finals and Wales defence coach Shaun Edwards is hopeful the centre will be ready.
Davies will miss the final Pool D game against Uruguay in Kumamoto on Sunday – which is scheduled to go ahead despite Typhoon Hagibis hitting Japan on Saturday – after being forced off with a knee injury against Fiji on Wednesday.
Victory for the Welsh will see them face France in a quarter-final, with England waiting if they slip up and fail to regain top spot from Australia.
Warren Gatland said during Friday's team announcement he was hopeful Davies will be available for the knockout rounds and Edwards indicated the situation had improved.
"We don't feel like it's as bad as we first feared," Edwards said on Saturday.
"There will be more news in a couple of days, but the medics are working hard on him and we're in a positive frame of mind with regards to him being involved further down the line."
Wales made 13 changes to the side to face Los Teros, with Hadleigh Parks and Josh Adams the only players retaining their spots.