Costa Rica midfielder Orlando Galo tested positive for a banned substance in September, the country's football federation (FCRF) announced on Tuesday.
Galo, 22, was found to have traces of anabolic steroid clostebol in his urine during examinations after a 2-2 draw with South Korea last month.
"The Costa Rican football federation announce that it has received a letter from FIFA notifying of the result of a doping test," the FCRF said.
"Orlando Galo Calderon tested positive for a banned product," it added.
Galo has between three and seven days to appeal and after the time period FIFA will decide whether to impose a suspension or not.
Los Ticos start their Group E campaign against Spain on November 23 before also facing Japan and Germany.
