The world football governing body, FIFA has suspended Ivory Coast goalkeeper Sylvain Gbohouo.
Fifa base its decision on alleged doping violation.
The Elephants were yet to face off Equatorial Guinea in their first game on Wednesday, in the ongoing Africa Cup of Nations in Cameroon.
The suspension comes as a blow to Patrice Beaumelle-led team as the 33-year-old was among his first choice.
Fifa said on December 26 that Gbohouo had tested positive for trimetazidine. However, according to the National team, this is a heart medication that the player has been undertaking.
The head coach confirmed that Gbohouo has appealed against the ruling.
"We had hope of getting a favourable response from Fifa but yesterday I learned that they were upholding their decision," Beaumelle said.
Gbohouo, who plays for Ethiopian football club Wolkite City, was among the 2015 Nations Cup-winning squad.
Ivory Coast are in Group E alongside holders Algeria, Sierra Leone and the Equatoguineans.
Their hope for tomorrows match lies in Badra Ali Sangare, Abdoul Karim Cisse and Ira Eliezer Tape, who their other three goalkeepers.