France could be without both Franck Ribery and Clement Grenier for the World Cup, according to reports in France, with Saints midfielder Morgan Schneiderlin one possible replacement.
Bayern Munich winger Ribery, Les Bleus' star man and a player with 80 caps to his name, has been struggling with a back problem for several weeks.
Having followed an individual training programme, he was due to rejoin the full squad on Friday in a bid to prove his fitness.
But French newspaper L'Equipe reported from the national team's camp at the Clairefontaine academy that both Montpellier winger Remy Cabella and Schneiderlin had been called up from coach Didier Deschamps' reserve list.
That prompted speculation that Ribery and Lyon midfielder Grenier would miss out on the trip to Brazil - the latter having sat out Friday's session while undergoing scans on a thigh problem.
Deschamps had already been forced into one change to his original squad, with injured Marseille goalkeeper Steve Mandanda replaced by St Etienne's Stephane Ruffier.