Real Madrid defender Pepe has said that a move to Porto would interest him.
The 29-year-old Portugal international admitted that he has thought about quitting La Liga, particularly after being banned for 10 games following an incident with Getafe's Javier Casquero in the 2008-09 season.
"There is a lot of pressure on the Portuguese in La Liga," he told Record. "After Casquero, I was forever marked throughout the world. They still call me assassin today. I was tempted to quit football.
"Porto is a club I would like to return to. It was a club where I learned a lot as a player."
Madrid currently sit third in La Liga and trail leaders Barcelona by 16 points.