The 31-year-old suffered the injury after clashing heads with US defender Matt Miazga during France's 1-1 draw with the United States in their last pre-World Cup friendly.

"After the injury, Olivier Giroud can't touch the ball yet with his head during the training for the next few days," said Deschamps.

The head coach added that he could not guarantee that defender Benjamin Mendy, who has recently returned to the pitch after being sidelined with a knee injury for nearly seven months, would be able to get back to his best shape.

"Regarding Mendy, I can't guarantee that he'll fully recover. However, he'll try to do his best and get back in shape as much as possible," Deschamps said.

He also said France striker Antoine Griezmann was a true team leader.

"Griezmann is the team leader. He smiles a lot, he's sociable and he enjoys life. He conveys everything he needs through emotions, he drives the team forward," the head coach said.

Russia's first-ever FIFA World Cup will take place from June 14 to July 15 in 11 host cities. France, who won their only World Cup on home turf in 1998, will face Peru, Denmark and Australia in Group C. Their first match will be against Australia in Kazan on 16 June.