Sir Jim Ratcliffe has identified ­Manchester United’s dire injury record as a critical area to address, believing this will hugely improve performance after a season when the squad sustained more than 60 injuries. Ratcliffe and his key lieutenant, Sir Dave Brailsford, are intent on strengthening United in the summer transfer window but are conscious that a squad of quality players is of no use if many are serially unavailable. Erik ten Hag’s selection and ability to have a consistent way of playing were constantly disrupted, with the defence particularly affected. The manager fielded 15 combinations in central defence and Luke Shaw, his first-choice left-back, played only 15 games. Shaw’s deputy, Tyrell Malacia, was unable to play all season. Brailsford, the director of sport at Ineos, Ratcliffe’s company, is leading the drive to improve the medical department’s performance, alongside Gary O’Driscoll, who became the head of sports medicine in September. O’Driscoll has assessed the department and, it is understood, initiated enhancements. There is confidence at the club that the benefits of O’Driscoll’s work will be fully realised next season. This includes extensive research into what caused so many problems. The rehabilitation of Raphaël Varane and Lisandro Martínez from injuries to play in Saturday’s FA Cup final ­victory over Manchester City is viewed as ­evidence of O’Driscoll’s impact. United want to sign Jarrad ­Branthwaite to form a first-choice centre-back partnership with ­Martínez, with Everton open to selling if their valuation of £60m-£70m is met. With Everton facing financial ­challenges and Sean Dyche, the manager, stating they may have to listen to offers for players, Branthwaite is their most saleable asset. However, it is thought the profitability and sustainability rules that Everton previously contravened may not be a factor this summer, allowing a firmer bargaining position with the club intent on not being held to ransom. With Rafael Varane departing, United need to add to their centre-back options with Varane departing and high quality lacking beyond Martínez, whose two seasons at the club have been hampered by injury. Harry Maguire began last season as a replacement and is 31, Victor Lindelöf remains a reserve and the 19-year-old Frenchman Willy Kambwala made his debut last term. Branthwaite impressed for Everton in a difficult campaign in which they were docked points but avoided relegation. The 21-year-old is part of Gareth Southgate’s 33-man England training squad for the European Championship that begins next month in Germany.