Firpo admits former Barca coach Ronald Koeman was the issue.
He recalled to Relevo: "I think Koeman didn't know me very well. He was the first one to tell me to stay, but that didn't turn into minutes later.
"I remember one time when Jordi Alba was injured and he put Dest at left back. The minutes he gave me were on the right… I had few. I had several games in which I played well, but I didn't have continuity. Then, a month without playing.
"I didn't understand that: at the most f***ed up moment, I'll take you out; 'If the game is going well or I can rotate, I won't put you on'.
"At first I was looking for explanations for his low participation, but Koeman gave me an answer in which he was not being honest: he told me that I was contaminating the group, so I stopped trying."