Iniesta will miss Saturday's Liga match at Getafe and Wednesday's Champions League Group G opener at home to Spartak Moscow but could be back for the Liga game against Granada a week on Saturday.
His Spain and Barca team-mate Jordi Alba, who was also called up for Friday's friendly against Saudi Arabia and Tuesday's World Cup qualifier in Georgia, has the flu and club medical staff will assess the full-back's health again on Friday, Barca added.
Forward David Villa, another Spain international, said on Wednesday he still needed some "running in" after recently returning to action following a broken leg sustained at the Club World Cup in December.
"I was out for many months, almost eight without playing, and that requires a certain recovery process," Villa said before Wednesday's training session.
"You have to be patient because rushing back now would not benefit anyone," added the 30-year-old, Spain's record scorer who netted on his first game back for both club and country.
"Everything I missed in the meantime won't come back however fast I go."