Manchester United are facing increased competition for Espanyol fullback Aaron Martin.
Sport says United have been monitoring the 20-year-old in recent months, with the Spanish side fearing that they will struggle to hold onto the Spain Under-21 international in the January transfer window.
But Napoli have identified Martin as one of their chief transfer targets, after Faouzi Ghoulam was hit with a cruciate knee injury.
Manchester City have also been linked with a move for Martin, after seeing Benjamin Mendy ruled out for the campaign.
Martin has a €30 million release clause, which rises to €40 million in the summer, which could put off the Italian side.