The two clubs are reportedly set to agree on a €10 million transfer fee, allowing the Argentine to move to English Premier League.
This is enough to suggest the Swans are preparing for life without centre-back Chico Flores, who is leaving the club to join Qatari side Lekhwiya.
Federico Fernandez has been a Napoli player since the summer of 2011, when he joined from Estudiantes, but he needed quite a while to nail down a regular starting berth at Stadio San Paolo.
It was only after impressing on loan at Getafe that the 25-year-old started proving his worth in Naples, making 25 Serie A starts last season.
He in turn started four matches for Argentina at the 2014 World Cup, but did not feature in the semi-final and final as Martin Demichelis was preferred by coach Alejandro Sabella.