The Spaniard was a late bloomer in his career, but impressed for the Gunners in 2015/2016, providing 27 goal contributions.
But by the summer of 2017, he felt frustrated at a lack of game time and the club not allowing him to move.
In a candid interview with La Voz De Galicia at the time, Deportivo La Coruna striker Perez said: "I feel cheated. In February I was not allowed to leave for a move to China with the promise that I would play more and after that I had even fewer opportunities. But the shirt number is an ugly gesture.
"On our pre-season trip, Lacazette asked the boss and he accepted. I was only told afterwards. Last year (Wenger) told me that he understood why I was upset. I think this season things will get worse, so help me out."
"Since I have been a professional footballer, I've felt happiest in Deportivo, surrounded by my family and my friends," he added.
"Put yourself in my place.
"I know I have chances to play for the national team and at the World Cup. But for that I have to play and I have to be happy. That's why I want to go back to Coruna. Arsenal are not behaving well with me.
"To take the shirt number without telling me and to give it to a companion - it seems to me that it is the last straw. I can't continue this way. I have given everything, but that has not been reciprocated, so I can't stand it any longer. I want to leave and be happy."