Jamie Roberts is backing young Wales centre Tyler Morgan to make a big impact against Fiji on Thursday night.
Wales' stunning 28-25 World Cup victory over England at Twickenham on Saturday came at a cost, with centre Scott Williams (right knee) and wing Hallam Amos (dislocated shoulder) ruled out of the rest of the tournament.
They join the likes of full-back Leigh Halfpenny (knee), centre Jonathan Davies (knee), centre Cory Allen (hamstring), wing Eli Walker (hamstring) and scrum-half Rhys Webb (foot) in watching the tournament from the sidelines.
Roberts will be partnered by Morgan, who wins just his second cap, in Thursday's match with Fiji in Cardiff.
Newport Gwent Dragons star Morgan, 20, was called into the squad following the injury to Allen, and he is coach Warren Gatland's fifth choice centre.
Roberts said: "It's difficult. I'm devastated for Scott and Hallam as well. I thought Hallam was outstanding on Saturday and I think Scott has been outstanding over the last few months. He's been playing the best rugby of his career.
"It's very difficult to watch the guys get injured and ruled out of the tournament. Hopefully their operations will go well.
"In comes Tyler, a young guy, and I think he was unlucky not to make the squad in the first place.
"He's a very explosive player. He's very enthusiastic and he has to put that into 80 minutes.
"He's a talented young fella. He will fit straight in. He's got experience around him in myself and Dan Biggar, George North and Alex Cuthbert as well.
"It's the same for [full-back] Matthew Morgan [who wins his second cap with Liam Williams ruled out with concussion]. He has to take care of his own job. The rest will happen for him."