Kalidou Koulibaly is said to be a target for Barcelona ahead of the summer transfer window as the La Liga giants continue on the hunt for a new world clash centre-back to bolster Ernesto Valverde's squad.

Napoli have turned down several approaches to sell the Senegal defender in recent times but Mundo Deportivo says that the Serie A side could be ready to cash in with him in the summer for around €60m (£53.5m, $70.5m).

Koulibaly, 26, has established himself as one of the best centre-backs around Europe since joining Napoli from Genk in the summer of 2014.

Antonio Conte tried to lure him to Stamford Bridge during the summer of 2016 with Napoli president Aurelio de Laurentiis claiming at the time that he rejected a €58m offer from the Blues.

Links with the Premier League champions re-emerged earlier this summer before Chelsea signed Germany defender Antonio Rudiger from Roma.

Mundo Deportivo claims that Juventus also expressed interest in his services following the departure of Leonardo Bonucci to AC Milan. However, Koulibaly stayed at Napoli having signed a new deal at the Serie A side until 2021 only months later, in September 2016.

Mundo Deportivo says that De Laurentiis promised Koulibaly that he would consider allowing him to leave in 2018 if an offer worth around €60m arrives.

The Spanish publication says that Barcelona are closely monitoring the situation as club technical secretary Robert Fernandez believes that he will be the perfect fit to strengthen Valverde's back-line ahead of the 2018-2019 campaign.

The report adds that Barcelona sent scouts to watch the defender in action during Napoli's 1-0 victory Roma on Saturday (14 October).

Mundo Deportivo say that the Catalans consider that his €60m valuation is too much to pay but the La Liga giants will surely need to break the bank in the summer to bolster the position amid the potential departures of Thomas Vermaelen and Javier Mascherano.

Barcelona are expected to sign Yerry Mina either in January or in the summer as they have first refusal to sign the Colombian international for €9m. However, Valverde may need a further centre-back to complement Gerard Pique and Samuel Umtiti with both Vermaelen and Mascherano having suggested in recent weeks that their days at the Nou Camp might be numbered.

"I still have a contract at the club but it is clear that maybe, once the season is over, I will see what I can do. But I have not yet spoken to anyone yet. From Barcelona they have always told me that they are happy with me. There will be time to think [about a potential summer move]," Mascherano admitted last week.

"It's clear that I'm playing less for my club because we have two centre-backs who are among the bests. I am trying to battle to win my place and especially to be ready when I am called on. When you have a better player ahead of you in the pecking order, you accept it and try to turn the situation around. I'm not the kind of person to get annoyed about it and even less with the managers."

Meanwhile, Vermaelen, speaking during the recent international break, suggested that he could leave the club in January in order to increase his chances of playing the World Cup in the summer.

"The national team boss [Roberto Martinez] says that the lack of playing time is not a problem at the moment but that he would take it into account from March onwards, when we will be close to the tournament. Who can predict if I will be still not playing at that time? Or if I haven't left the club during January transfer window?" Vermalaen said.