The highly-rated 16-year-old trained with the first team for the first time as Ernesto Valverde put his side through their paces.
Fati has been at Barca since he was 10 years old and is seen as being one of La Masia’s brightest stars. He was handed a new contract in July with a €100m buyout clause.
Barcelona are light on options in attack for Sunday’s game. There will be no Ousmane Dembele for the next few weeks, Luis Suarez is also out and Lionel Messi is still not back in full training.
Youngsters Carles Pérez and Abel Ruiz also trained with the team on Wednesday morning, and it’s likely we may see some of the youngsters included in the squad for Sunday’s game.