The Fiji Rugby Union has officially confirmed this.
This unfortunate setback means that he will be unable to participate any further in the tournament
Teti Tela is set to step in and take the field against Wales on Monday.
Muntz, who made his debut for Fiji earlier this year, had been in exceptional form and played a pivotal role in Fiji’s impressive 30-22 victory over England just two weeks ago.
Coach Simon Raiwalui said its most devastating for them as a group and for Muntz.
The mentor says the number 20 has worked so hard for the past two years with the Fijian Drua and for Flying Fijians.
He say they feel for him as a young man he misses the opportunity so close to the Rugby World Cup.
Raiwalui says they have got 33 players and have the utmost confidence in them, adding once they name the team for the match against Wales they will have utmost faith in those selected.