Manchester United will only have a limited 15-day window to lure Napoli defender Kim Min-jae to the club this summer as Erik ten Hag eyes a replacement for Harry Maguire. The South Korean has emerged as a transfer target for the Red Devils in a move that would reshape their backline as England international Maguire edges closer towards the exit.United are one of several clubs interested in the towering centre-back Kimafter impressing since his £15m move from Fenerbahce this summer, having replaced Kalidou Koulibaly, who joined Chelsea.The 26-year-old has proved to be one of the key defensive linchpins in Luciano Spaletti’s side, who are eight points clear at the top of Serie A, and Ten Hag has identified the South Korea international as a potential signing with Maguire’s future uncertain.However, the deal to sign Kim is likely to be difficult to pull off due to a time-sensitive minimum fee release clause inserted into his contract when signing a four-year contract with the Partenopei. Reports suggest the release clause has been set at £43.8million (€50m), which would prove to be an affordable value for a club of United’s size, and is only available for a set period in the summer of 2023.READ MORE: Man Utd’s expected price tag for Harry Maguire with sale planned Harry Maguire: Erik ten Hag has his sights set on a replacement (Image: Getty Images/Express Sport)Napoli sporting director Cristian Giuntoli refused to divulge if the amount mentioned was accurate, but explained there is only a limited window of opportunity for interested parties to prise him away from the Stadio Diego Armando Maradona – and confirmed talks are ongoing over a new contract.’It is only valid for foreign clubs and it is accessible in a window in July for just 15 days,’ he told Corriere dello Sport.When asked about the specific value, Giuntoli added: ‘It is variable, it depends on the revenues of the potential buyer. It is all theoretical given that we are already thinking about changing these terms.”DON’T MISSTottenham shown what they’re missing after failed Kim transferMan Utd boss Ten Hag ‘to sell Maguire and release Fred’Man Utd must avoid Maguire and Rojo World Cup repeats Kim Min-jae: Man Utd are reportedly keen on the Napoli man (Image: Getty Images)