The 33-year-old rejoined the national side on Monday after being recalled by new coach Fernando Santos, along with central defender Ricardo Carvalho, who has been out in the cold for three years following a bitter dispute with previous coach Paulo Bento.
"I'm very happy after being away from the national side for four years," Tiago told reporters. "At that time, I felt that I could not give anything more to the side, I felt down.
"I regret sending a fax at that point, despite feeling that it would be the final point in my international career.
"Sometimes we feel we need a break or a rest, but sending the fax isn't the best option. Sending a fax is not something that any player should do."
Tiago, whose previous appearances were at the 2010 World Cup in South Africa, said he wanted to return last season but did not feel the timing would be appropriate.
"I wouldn't feel right returning before the World Cup, I wouldn't want them to think I was just returning to play at the World Cup," he said. "Now we have a new coach who asked if I would be available, and I said yes.
"It's not easy to be here today after saying that I did not want to return. It's not easy to turn back, so we should never close the door. That's a bad example that I have set."
Former Real Madrid and Chelsea defender Carvalho was recalled by Santos at the age of 36, having quit the side three years ago after saying he was "disrespected" by Bento.
Bento quit last month after Portugal lost 1-0 at home to Albania in their opening Euro 2016 qualifier.
Portugal face France in a friendly on Saturday and travel to Denmark for a Euro 2016 qualifier the following Tuesday.
(Writing by Brian Homewood in Berne, editing by Stephen Wood)
Share
