 De Visser also recommended the hiring of Frank Arnesen to Abramovich, a move which was opposed by then Chelsea manager José Mourinho.It was also De Visser who first recommended the signing of John Obi Mikel and Salomon Kalou to Frank Arnesen for Chelsea.De Visser and Arnesen later clashed with former Chelsea manager Mourinho over transfer policy, with the two allegedly recommending Alex be brought over from PSV to solve the club's defensive problems, while Mourinho was said to have preferred Khalid Boulahrouz instead.