Barca spent 55 million euros on Ferran as an up-front fee, with that amount potentially reaching 65 million euros with add-ons, but the restraints placed on the club by LaLiga currently prevent the 21-year-old from being registered until players are shipped out of the Camp Nou.
"I'm calm," Ferran said when asked about the club's troubles registering him. "They're doing all they can, they're working on it.
"My recovery is going well. I'm over the injury and I'm fine. I hope to be ready soon, even for the Supercopa [de Espana]. I like challenges."
"That's an internal matter, but the most important thing is that I'm a Barcelona player now," Ferran said.
"I learned a lot from him and I have very good memories from my time at City. I learned a lot.
"I've always said that I wanted to return to one of Spain's big clubs, so when Barcelona came in for me I didn't think twice about it. It's a great opportunity for me.
"This is a special time for me and for my family. I'm very grateful. Now it's time to enjoy this day with the fans and I can't wait to play."