He said this on his Twitter
After the club has announced that they will present arguments to the red card shown to Gerard Pique at the second leg of the Spanish Super Cup, the same player finally spoke about the controversy. Through a message on Twitter, the Catalan wanted to apologize for his attitude, but also to make clear that at no time he insulted the assistant referee.
"I apologize for the attitude with which I protested to the referee. It was not correct. It was a match of high tension in which we had a lot to win. However, at no time I used any kind of insult to his person."
Remember that Piqué complained about a possible offside of Athletic. The referee wrote he had said "Me cago en tu puta madre!", something like "fuck your fucking mom."