France duo Yann M'Vila and Blaise Matuidi are both unlikely to feature in the Group D opener against England at Euro 2012.
Rennes holding midfielder M'Vila injured himself in the first minute of the 2-0 friendly win over Serbia last Thursday. He was feared to be a doubt for the entire tournament but will remain with the France squad.
A statement from the French Football Federation said: "The MRI confirmed that it's a moderately serious sprain, without aggravating factors.
"It's running its course, there are no complications."
Paris Saint-Germain midfielder Matuidi will definitely miss the encounter with the Three Lions on June 11 after suffering a minor tear to his right hamstring.
M'Vila and Matuidi are likely to be replaced in the heart of the French midfield by Newcastle United's Yohan Cabaye and Marseille's Alou Diarra.
Goalkeeper Steve Mandanda is fit however for the England game, after recovering from a toe injury.
France face their final Euro 2012 warm up match when they meet Estonia in Le Mans on Tuesday.