The 27-year-old joined City in a €24million deal from the Spanish side int he summer.
He told Radio Catalunya: “I will be back in Barcelona to play, not as a tourist. I want to return to Barcelona, because to leave was the hardest moment of my life.
“Sergio Busquets is very good person, and without Busquets, I would not have gone. He has a great quality and what I want are games, not sitting on the bench. I won everything there and needed other challenges.
“For me, Manchester City is a very nice challenge. This is a team that is not playing in the Champions League, and that has not won any titles recently. Therefore, they are perfect for me.”
