The France international, who has impressed fans since joining from Lille in July 2011, has not played since his side's 1-0 Premier League loss to West Ham on 11 November.
He has had surgery in Paris but Pardew said the injury required further attention.
"He's had one side of his groin done and that caused a potential weakness in the other side, so that needs to be done," he told reporters.
"That will be done I think, today or tomorrow and he will probably be out for eight weeks."
Pardew also said defender Steven Taylor was likely to be out for a similar period of time with a hamstring injury.
Newcastle are missing 11 senior players for Wednesday's match at Stoke City.
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