The Catalan outfit were found guilty of breaching rules in relation to "the international transfer of minors" earlier today.
However, the Spanish champions are confident that the situation can be resolved on appeal.
"We are calm and we will give our explanations to FIFA," a club source told AS.
"It is a normal process and we have 90 days to argue and explain why we signed these players. Also it's wouldn't have been two years. It would have been two transfer windows."
Barcelona drew 1-1 with Atletico Madrid in the first leg of their Champions League quarter-final at the Camp Nou last night.