Aberdeen have requested that Sone Aluko returns to be assessed by the club's medical staff before linking up with Nigeria's Under-20s.
The 20-year-old already joined his international team-mates at their Spanish training camp without the Dons' permission.
Manager Mark McGhee believes Aluko's departure is down to a misunderstanding and he wants him back at Pittodrie so he can be assessed before the club can allow him to return with their blessing.
100 per cent
Aluko came off the bench in Monday's goalless draw with Falkirk and Aberdeen's manager wants to make sure he is 100 per cent to take part in the Under-20s World Cup.
"In fairness there may have been a bit of a misunderstanding," McGhee told the club's official website.
"We're in contact with the Nigerian FA and are insisting that Sone returns to Pittodrie to be fully assessed by our medical staff before we decide whether we will give him permission to take part in the tournament."