Both players are currently being assessed by specialists to establish an accurate prognosis.
James Hook and Gareth Anscombe, who were both part of Wales’ Rugby World Cup training squad and featured in warm-up tests ahead of the tournament have been called into the squad as replacements.
Hook will feature in his third RWC squad and will look to add to his tally of 78 international caps. Anscombe made his international debut against Ireland in August.
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.
*Above is subject to Rugby World Cup confirmation