Chelsea FC has signed a £35m Premier League star to strengthen their defence, with the new player set to replace Marc Cucurella. The Blues have been struggling to find a consistent defensive partnership, and this signing could be the solution. The new player, who has not been named, is reportedly available for a fairly modest fee of £35million. In the grand scheme of Chelsea's other investments in recent years, that's a snip for a Premier League-proven asset in the prime of his career. Given Fofana and Colwill's fitness issues in recent years, another senior centre-back presence looks like a major requirement. However, left-back also looks set to become a major concern amid reports Marc Cucurella has handed in a transfer request. To that point, Valentin Barco is already seemingly waiting in the wings as the ideal choice. The Argentina asset has already announced he'll be leaving Chelsea's sister club, Strasbourg, after impressing over the past season-and-a-half in France. The BlueCo connection promises to streamline any negotiations over a deal, which makes a move for Barco even more appealing. The South American has played his best football in Ligue 1 as a midfielder but initially joined from Brighton as a left-back. That could make him the perfect deputy to give Hato a chance to make the left-back role his own. Chelsea have also already secured the signature of Brazilian left-back Denner, who will arrive from Corinthians this summer. Right-back takes care of itself with Reece James and Malo Gusto continuing their rotation, with Josh Acheampong also in that conversation. However, there remains some uncertainty in the goalkeeper position behind No. 1 choice Robert Sanchez. The Sun reported that back-up Filip Jorgensen has asked the club to explore a move away after failing to get more minutes in west London. If Jorgensen leaves, that could see Gabriel Slonina promoted to the deputy role while 23-year-old Teddy Sharman-Lowe takes on a more senior position as third choice.