The Argentinian admitted the opportunity to link up with his compatriot Mauricio Pochettino, the Espanyol coach, was too great to turn down.
He told AS: "It has been a difficult decision for me because Deportivo is my home. They opened the door to Europe for me and I am very thankful, but then this possibility arose and I think I have done the right thing.
"It is important to have a winner as a coach and someone who is demanding of his players, someone that always wants more.
"I am coming here with the idea of growing as a player and improving an already-consolidated group. I want to fight for important goals this season."