He said: "Let's get the elephant out of the room and I want to talk about it once: the first thing is to say that the club was aware of my journey. It is important and it changes the situation.
"The other thing, when we talk about keeping something hidden, I secretly parked the car outside, secretly walked past 15 people, took pictures with people on the way there and got on the plane.
"If you disregard some of the things that were done behind the club's back and which did not happen, the most important thing is that it was a mistake.
"The trip was a mistake and the timing was completely wrong, it didn't seem that way at the time."
He also said: "It is my mistake, which I have to accept and live with. It didn't seem that serious at the time, but when you think about it, it's very obvious.
"I also want to publicly apologise to the Sporting fans, the staff and the players for the mistake I made."