Nayacalevu's World Cup over
The 25-year-old Stade Francais flyer sustained the injury during the 28-13 Pool A defeat by Australia at the Millennium Stadium on Wednesday and coach John McKee has since confirmed his departure from the squad.
Nayacalevu, who also featured in Fiji's 35-11 defeat by England at Twickenham in the opening game of the tournament, is to return to his French club Stade Francais for treatment and rehabilitation.
France-based Timoci Nagusa will join the Fiji squad to replace Nayacalevu. Nagusa has been playing on the wing for French club Montpellier since 2010.
McKee said scrumhalf Nikola Matawalu, who suffered bruising to his lower back against Australia, is expected to be available for training and selection.
Fiji's next Pool A fixture is against Wales at the Millennium Stadium on Thursday.
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