Sevilla striker Munir El Haddadi has lost an appeal for the second time against a FIFA decision that stops him switching allegiance from Spain to Morocco.
The 25-year-old had hoped that a recent change in the regulations would allow him to make the change, but FIFA refused his application in September.
The Court of Arbitration for Sport also said on Friday that it had rejected his appeal.
“The case has been dismissed by CAS and the challenged decision has been confirmed,” it said.
FIFA rules bar players from changing national teams once they have played a competitive international, even if they hold dual nationality.
As a result, El Haddadi was tied to Spain after a single appearance for them in a European championship qualifier against Macedonia in September 2014.
He had come on as a substitute then and played less than 15 minutes.
El Haddadi and the Moroccan federation appealed to CAS before the 2018 World Cup but it was rejected.
In September, FIFA tweaked the rules so that players with dual nationality can change allegiance provided they have not played more than three senior competitive matches for their first national team.
They must also not have played in any competitive internationals, at any age level, after their 21st birthday.
Haddadi had played three competitive matches for Spain’s under-21 team after his 21st birthday.