Barcelona have identified Napoli centre-back Kalidou Koulibaly as a potential transfer target. The Senegalese defender has just a year remaining on his current deal with the Serie A club and could therefore be available for a bargain price.According to Mundo Deportivo, Barcelona view Kalidou Koulibaly as an alternative to Sevilla defender Jules Kounde, who is believed to be close to joining Premier League giants Chelsea.The Catalan giants are eager to sign a world-class defender to bolster their defense ahead of next season. Furthermore, the club will be eager to sign a long-term replacement for 35-year-old centre-back Gerard Pique, who is approaching the latter stages of his career.Kalidou Koulibaly has developed into arguably one of the best defenders in Serie A during his time with Napoli. The 30-year-old has made 317 appearances for the club in all competitions and has helped them win a Coppa Italia title. His physical presence, experience, and leadership qualities make him the brilliant replacement for Pique at Nou Camp.Napoli are believed to be keen to keep hold of the defender and are expected to offer him a contract extension. However, the defender does not fancy staying in Naples as he is seeking a new challenge. The Italian giants could therefore be forced to sell him this summer rather than risk losing him on a free transfer next year.Reports suggest Napoli president Aurelio de Laurentis could demand a fee in the region of €35-40 million for Koulibaly. Barca are rumored to have tabled an offer to the defender's agent Fali Ramadani.Barça Universal@BarcaUniversalBecause Jules Koundé is practically impossible, Barça have decided to go for Kalidou Koulibaly. His agent will present Napoli with an offer from Barcelona in the coming days. They'd accept to sell him for €35-40m.— @sportmediaset37423Because Jules Koundé is practically impossible, Barça have decided to go for Kalidou Koulibaly. His agent will present Napoli with an offer from Barcelona in the coming days. They'd accept to sell him for €35-40m.— @sportmediaset https://t.co/p6kYBfKw7TBarcelona could target the signing of Chelsea defenderChelsea v Leicester City - Premier LeagueBarcelona are expected to prioritize signing a top-quality left-back this summer as they lack adequate cover and competition for veteran defender Jordi Alba. Chelsea left-back Marcos Alonso has emerged as a potential target for the Catalan giants as per Fabrizio Romano.According to the Italian journalist, the Blaugranas are in advanced talks to sign the Spaniard, who is rumored to be keen to play in La Liga in the near future. Alonso has just one year remaining on his contract with the Blues and could therefore be available for a bargain price this summer.Fabrizio Romano@FabrizioRomanoSergi Roberto’s new contract until June 2023 will be announced by Barcelona on Friday, as @gbsans said - and he will reduce his salary to stay at Barca. 🤝 #FCB…but Barça remain in negotiations for both Azpilicueta and Marcos Alonso, still waiting for Chelsea decisions. twitter.com/fabrizioromano…Fabrizio Romano@FabrizioRomanoAfter many changes and twists, Sergi Roberto will finally sign his new deal with Barcelona later this week. The plan is to complete it on Friday, as per @tjuanmarti @relevo. 🤝 #FCBNew deal will be valid until June 2023 already approved by Xavi. twitter.com/fabrizioromano…7537500After many changes and twists, Sergi Roberto will finally sign his new deal with Barcelona later this week. The plan is to complete it on Friday, as per @tjuanmarti @relevo. 🇪🇸🤝 #FCBNew deal will be valid until June 2023 already approved by Xavi. ⤵️ twitter.com/fabrizioromano…Sergi Roberto’s new contract until June 2023 will be announced by Barcelona on Friday, as @gbsans said - and he will reduce his salary to stay at Barca. 📑🤝 #FCB…but Barça remain in negotiations for both Azpilicueta and Marcos Alonso, still waiting for Chelsea decisions. twitter.com/fabrizioromano…The 31-year-old's technical ability, attacking play and experience make him the ideal transfer target for Xavi Hernandez's side.