FC Barcelona have made it clear they would prefer not to lose Ansu Fati for the best part of the month when the U17 World Cup kicks off in October. Now he's officially a Spanish citizen, Ansu is available for selection.

According to SPORT's research, Barça will be unable to block a call up should Ansu make the final squad list. This despite the tournament not being part of FIFA's official calendar.

FIFA present an official tournament list every year and if a player is selected, the clubs are forced to release them to represent their national team. This tournament isn't included and, as such, Barça aren't bound by FIFA to let Ansu join up with Spain next month.

However, Spanish law goes against that. This rule is to ensure clubs make players available for their national team at any age level and failure to do so could result in heavy financial sanctions and future problems for the player.

This rule is only applicable to Spanish players. This means should a Brazilian youngster be picked for a tournament not part of FIFA's calendar, Barça would decide whether to let them go or not. But as Ansu is now a Spanish citizen, the law does apply to him.

All eyes will now be on Spain's final 21-man squad list on the eve of the tournament's debut.