Wales have called up James Hook and Gareth Anscombe after it was confirmed Scott Williams and Hallam Amos will miss the rest of the World Cup.
Scarlets midfielder Williams (knee) and Newport Gwent Dragons back Amos (shoulder) went off during the second half of Wales' 28-25 Pool A victory over England at Twickenham on Saturday.
The Welsh Rugby Union announced that the pair have been released from the squad, with Gloucester back Hook and Cardiff Blues' Anscombe called up as replacements.
Amos said on Twitter: "Overwhelmed by all the messages about the match and my shoulder, thank you to everyone for their kind words."
Hook will feature in his third RWC squad and will look to add to his tally of 78 international caps. New Zealand-born Anscombe made his international debut against Ireland in August.
"Both of them have played in our friendlies prior to the World Cup starting," said attack coach Rob Howley. "James is vastly experienced and can play many positions and Gareth gives us that ability to play at 15. The door opens for them.
"It is a blow to lose two more players but we showed resilience and character at Twickenham on Saturday and I'm sure you'll see that in abundance in the next few weeks."
Liam Williams sustained concussion in the same game and will not be considered for the Fiji fixture due to the impending time frame of the game. He will be continually assessed and is to undertake a graduated return to play before being considered for selection for Wales' following game against Australia.
Wales have now lost five injured players from their original World Cup squad, with Williams and Amos joining Leigh Halfpenny, Rhys Webb and Cory Allen.