Jason Wilcox, director of football (left), and chief executive Omar Berrada, will be key figures in Manchester United's transfer moves The acquisition of a new central midfielder is viewed as the priority for Manchester United this summer. Elliott Anderson, Carlos Baleba, Adam Wharton and Sandro Tonali are all targets to replace the outgoing Casemiro. In a nutshell, it is farewell number 18 as the Brazilian departs and hello number six - the crucial, modern defensive midfielder the Old Trafford club want to replace him with. But it is never that simple. Here, BBC Sport looks at how United's search is shaping up. 'It's the ultimate role' - Carrick on Man Utd job There are two key factors linked to that hunt that require settling before United can map out their path towards signing Casemiro's successor. First of all, Champions League qualification will be a crucial element. Players are still attracted to United regardless of European qualification.…