Ilias was registered on Monday even though Barca knew he wouldn’t be able to play against Benfica due to suspension, according to Ara.
However, the move means that the 17-year-old could now play in Barca’s final group game at Bayern Munich on December 8.
It could be that Ilias is needed too. Barca will still be without Sergio Aguero and Martin Braithwaite, and it’s not clear if Ansu Fati will be fully fit in time for the crucial game.
Xavi handed Ilias his first-team debut in his first game in charge against Espanyol. The 17-year-old played the first 45 minutes and was replaced at half-time by Ez Abde.
Neither Ilias nor Abde were able to feature against Bayern Munich which meant Xavi turned to Yusuf Demir for the game at the Camp Nou.
It will be interesting to see how Xavi lines up his team on Saturday against Villarreal with the youngsters seemingly clearly in his plans for the future.
The new boss also has Ousmane Dembele back in the reckoning after the Frenchman made his return from injury as a substitute against Benfica.