Manchester United's proud record of boasting an academy player in every matchday squad since 1937 is under threat after Kobbie Mainoo went down injured with an 18-year-old drafted in to travel down to London. The Red Devils face Tottenham in the capital on Saturday lunchtime but will be without Mainoo, who has often been on the bench for them this season. It is a setback for the homegrown talent, but his absence leaves a major hole in the squad for Ruben Amorim. United's tradition of backing