Charlton have had their work permit application for Costa Rica winger Christian Bolanos rejected.
Bolanos played for Costa Rica in the 2006 World Cup
The Home Office turned down Charlton's request at a hearing on Tuesday after Bolanos failed to meet the requirement of appearances for his country.
"Christian is an emerging talent and is a fixture in the Costa Rica side though he's only 22, so it's disappointing for us and for him," said boss Iain Dowie.
Bolanos had agreed a loan deal from Deportivo Saprissa.
Bolanos was in his country's squad for the 2006 World Cup and was signed for the Addicks after impressing during a trial spell with the club.