Chelsea poised to buy £33.8m Koulibaly from Napoli and confirm Sterling arrival

The Senegalese should be the first of at least two centre-backs to join

TEAMMATES: Chelsea's Reece James and Manchester City's Raheem Sterling. Photo credit: Nick Potts/PA Wire.

Chelsea are on the verge of boosting their defensive options after agreeing a €40m (£33.8m) fee with Napoli for Kalidou Koulibaly, who is close to sealing a move to Stamford Bridge on a four-year deal.

The agreement came as Raheem Sterling completed his transfer from Manchester City for a fee worth up to £50m on a contract to 2027. The England forward has flown to Los Angeles to join his new teammates on their pre-season tour of America.

Thomas Tuchel is keen to sign at least two centre-backs and Todd Boehly, Chelsea’s co-owner, has moved swiftly in talks with Napoli over Koulibaly. The 31-year-old is understood to have agreed personal terms and the move should be completed soon.

The deal for Koulibaly, who has developed into one of the best centre-backs in Serie A since joining Napoli in 2014, will come as a major relief for Tuchel. The departures of Andreas Christensen and Antonio Rüdiger have left a huge hole in Chelsea’s defence and Tuchel has seen Bayern Munich muscle in one of his biggest transfer targets – the Juventus centre-back Matthijs de Ligt.

Bayern’s interest in De Ligt forced Chelsea to look elsewhere and they turned to Koulibaly, who has one year left on his deal. The Senegal international should provide welcome experience and leadership.

Chelsea are also hopeful of completing the signing of Nathan Aké from Manchester City this week. Aké has agreed personal terms and the deal should go through once Boehly settles on a fee with City, who are demanding at least £40m for the Netherlands centre-back.

With Aké expected to slot in on the left of Chelsea’s back three, Tuchel could also urge the hierarchy to move for Paris Saint-Germain’s Presnel Kimpembe or Sevilla’s Jules Koundé. Torino’s Gleison Bremer has also been scouted, though he is expected to join Internazionale. Juventus are also looking at Bremer.

Chelsea, who could loan Hakim Ziyech to Milan, will look to bring in another forward after signing Sterling. Milan’s Rafael Leão and Bayern’s Serge Gnabry are of interest to Tuchel. There is also interest in Bayern’s Robert Lewandowski, who wants to join Barcelona, but there are doubts over whether Tuchel will tell Chelsea to bid for Manchester United’s Cristiano Ronaldo.

On Wednesday Sterling has thanked Manchester City and their supporters in a farewell message. He wrote on Twitter: “What a ride it’s been. I am thankful for the ups and the downs, as it’s the downs that have, at times, tested my strength and resolve and enabled me to stand here in front of you as the best possible version of myself. I arrived in Manchester a 20-year-old. Today, I leave as a man.” In an interview with Chelsea’s website he said he felt he had “much more to achieve” and added: “London is my home and where it all started for me, and it’s amazing I now have the opportunity to play in front of friends and family week in, week out at Stamford Bridge.”

Guardian