French captain Amelie Mauresmo told L'Equipe that she had been unable to train on Wednesday and Thursday.
"The doctor says it's the flu. Currently she is in bed resting," said Mauresmo.
Mauresmo added that that she would give the French No.1 until the last possible moment before making a decision on her team.
"We will check on her tonight (Thursday) and especially tomorrow (Friday) morning," she said.
Bartoli refused to play for France for eight years as the team rules exclude parents or private coaches from being involved during Fed Cup weeks. She is coached by her father Walter.
Mauresmo recently convinced her to return.
Kristina Mladenovic, Virginie Razzano, Pauline Parmentier and Alize Cornet have also been called up for the clash.