​Man United determined to sign top defender for Mauricio Pochettino in JanuaryManchester United have reportedly made another mid-season managerial change following the club’s disastrous start to the campaign under Michael Carrick.Carrick was shown the exit door earlier this week after winning just one of the first 10 Premier League matches this term.However, the former head coach was far from United’s biggest problem, and it would take further changes to steady the ship in Manchester.Manchester United want to strengthen their defence in JanuaryNew Manchester United head coach Mauricio Pochettino is inheriting a defence that has conceded the most goals across all competitions among the clubs in Europe’s top-five leagues.According to the Mirror, Manchester United are “ready to dip into the market” to strengthen their squad, with a “top defender” the number 1 priority.It is understood United have been reluctant to do business in the winter window, but there is an “acceptance that they need reinforcements in defence.”Jason Wilcox and his team frustratingly overlooked the area last summer, with an aim to address it in the summer of 2027. However, that decision has proven costly, resulting in the Red Devils regressing.Pochettino will now be backed in January with “major transfer funds” and will reportedly get a say on targets as part of United’s vision for success with their new manager.The Mirror adds that United are also likely to look at a forward, but a big-name striker is more likely for the summer. They reportedly intend to bring forward the plan for a defender to arrive in January.Three Premier League stars being eyedRecently, The Peoples Person relayed a report claiming United have three defenders on their radar ahead of the January transfer window.Brentford centre-back Nathan Collins and Fulham’s Calvin Bassey have joined Jarrad Branthwaite of Everton on the list of potential targets.All three defenders are more physically dominant and better suited to playing in a high-line system than United’s current defenders, but it may prove very difficult to sign a top player from a Premier League club mid-season.Outside England, United have been strongly linked with Como defender Jacobo Ramón, who most recently showed his qualities in Como’s 4–1 win over United in the Champions League.