Aguirre will be replaced by the club’s former goalkeeper Abel Resino.
Aguirre told Cadena SER: “I am the first one to recognise that I am part of the problem.
“One must think about the future of the club and, above all, I want to say that this has been a gentleman’s agreement.
“It is the easier thing for everyone, less traumatic. I only have words of gratitude for the club and I am leaving with no grudges.
“I wish Abel all the luck in the world. He was doing very well with Castellon and is a good coach as well as a friend.
“Besides, I am convinced that the team will finish in the Champions League positions.”
