Wales confronted a mounting World Cup injury crisis with try hero Cory Allen expected to exit the tournament.
Coach Warren Gatland said Allen, who got three of the eight tries in Sunday's 54-9 victory over Uruguay, suffered a “significant” hamstring tear.
He was to undergo a scan on Monday.
With Wales to play England in one of the crunch matches of Pool A on Saturday, there are doubts about front row pair Paul James and Samson Lee, Aaron Jarvis has a damaged rib while full back Liam Williams left Sunday's game with a thigh injury.
Gatland has already had to patch up the team after star full-back Leigh Halfpenny and first-choice backs Rhys Webb and Jonathan Davies dropped out before the tournament started.
“It looks like Cory Allen's done a significant hamstring injury,” said Gatland.
Medics had told him “it looks like he'll definitely need to be replaced.”
Gatland also has front-row troubles which also may need a replacement.
Tighthead prop Lee, making his comeback from a ruptured achilles tendon sustained, went off at half-time, loosehead Paul James after just 32 minutes.
James' replacement Aaron Jarvis, also the back-up hooker in a 31-man squad boasting only two specialists, played the last 20 minutes in major pain.
“Liam Williams got a knock on the thigh, Samson Lee and Paul James have got tight calves, and Dan Lydiate had a head assessement and has passed that so he's able to take a full part in training next week,” Gatland said.
“Aaron Jarvis actually popped a rib cartilege as well, nothing that's too serious but he was in quite significant pain.
“He really dug in deep for the last 20 minutes on the field.”
Gatland admitted he might have some tough decisions to make on Monday when a clearer medical picture appears.
“We may have to make a tough decision on the props,” the Kiwi acknowledged.
“We're carrying five props and at the moment we've only got three who can take the field, and we have to have four, so we may have to make a difficult call and replace one of the props.”
The Kiwi coach dismissed any link between the injuries and Wales gruelling training regime.
“Sometimes you just get a little bit of bad luck,” he said.
“We felt very happy with the way we prepared and trained, but unfortunately we've picked up a few knocks but that's rugby, that's professional sport, there's no doubt we'll pick a few more.”
“The medical and conditioning staff have done a brilliant job. Sometimes it happens that you go through a spate of picking up a few injuries and you just have to deal with that.”
Gatland said that despite the injuries and having to play at Twickenham, he was still confident Wales could win. Six first team regulars were rested for Sunday's match.
“As a team, we're confident in our own ability. As a stadium, I think it's one of the best rugby stadiums,” Gatland said.
“England have had success there but we've had success there and as a coach I've had a huge amount of success. I look forward to going there.”
Wales go on to play Fiji on October 1 and perhaps the pool decider against Australia on October 10. – AFP