Cissokho called up to replace Tremoulinas
"He has thigh pains," Blanc told reporters at the French training camp in the outskirts of Paris, adding that the Girondins Bordeaux player was being replaced in the squad by Olympique Lyon's Aly Cissokho.
Arsenal midfielder Abou Diaby is also a major doubt for Saturday's game against Romania because of an ankle injury.
"He might be too short," said Blanc of Diaby who has not trained all week. "A final decision will be made on Thursday night or Friday morning."
France, who have three points from two games, take on Romania at the Stade de France on Saturday and play Luxembourg in Metz on Tuesday.