Sevilla attacker Munir El Haddadi, who has already been capped by Spain, has again had his hopes of playing for Morocco dashed after the Court of Arbitration for Sport (CAS) rejected his appeal on Friday.
It marks a second disappointment for the 25-year-old who originally applied for a switch of colours before the 2018 World Cup.
A recent reform by FIFA of rules concerning dual-national players had raised his hopes and pushed Morocco to call up the former Barcelona winger.
El Haddadi played once for Spain in 2014, a European Championships qualifier against the Former Yugoslav Republic of Macedonia and was involved until 2016 with the national under-21 team when, crucially, he was himself older than 21.
The new FIFA rules, adopted in mid-September, allow switches but the player, who must hold two passports, must be under 21 years of age in the last match played with their first nation.
El Haddidi had been denied the chance to join the Atlas Lions in September.
"The CAS procedure was conducted on an expedited basis at the parties' request so that the final decision could be rendered before Morocco's next matches in the 2021 African Cup of Nations," explained the court based in Lausanne.
"In view of the urgency, the panel of arbitrators in charge of the procedure has issued its decision, without the grounds, which will follow in due course."