Barcelona reportedly scouted Kalidou Koulibaly during Napoli's Serie A clash with Lecce at the weekend.
Earlier this week, it was alleged that the Spanish club's director of football Eric Abidal had travelled to the Italian league game to watch Napoli midfielder Fabian Ruiz in action.
However, according to Marca, Abidal was also there to keep tabs on Koulibaly, who is widely regarded as one of the best central defenders in world football.
The 28-year-old, who was linked with both Manchester United and Real Madrid during the summer, has made over 200 appearances for Napoli since arriving from Genk in 2014.
Gerard Pique and Clement Lenglet are currently Barca's first-choice centre-back pairing, but back-up Samuel Umtiti - currently on the sidelines through injury - has been strongly linked with an exit.
Napoli are said to be unprepared to sell the Senegal international unless his £110m release clause is activated.
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