Despite starting all three Primera Division games so far this term, Fabregas remains far from happy playing a cameo role for his boyhood club, having returned to the Nou Camp last northern summer after eight years at Arsenal.
He told Radio Marca: "There's no such thing as a great substitute in the world of football.
"I couldn't tell you what makes a great substitute.
"I always wish my team-mates well and put a happy face on.
"If I have to take my unhappy face home then so be it, but I would never let my team-mates or manager see it."
The versatile 25-year-old competes for a starting berth in the centre of the park with
"Everybody likes to play every minute of the season," he added.
"I've always said that I play for the best team in the world, but I came here to compete, to learn and enjoy, not to sit wracking my brains.
"The manager knows what I can offer. But across the three positions that I can play, I am competing with the three best players in the world.
"I'm delighted to be a part of this team but when a coach tells me I have to go, I'll go.
"But I will not make it easy for him to do so, by any means. I will keep going, looking forward to the time that things change.
"I came here to see out my career."
Spain champion Barcelona has agreed the signing of