Born Israel Copitch, his family were originally called Copatz and came from Lithuania. He was always known as ‘Jack’ and surprisingly displaced Billy Halsall after only a handful of reserve team appearances, when joining the club from Manchester junior football. The Southport Guardian said of him, ‘He has a splendid power of anticipation, handles the ball cleanly and kicks strongly’. The experiment was not a success; Doncaster scored 9 goals in the two Christmas games and Halsall was quickly recalled. Jack is numbered among comparatively few Jewish players to have attained Football League status. His brother William (‘Wolfie’) played for Tranmere Rovers, Stockport County and New Brighton. They were almost certainly the only pair of Jewish brothers to appear in League football. He was a shopping bag manufacturer for many years and died of cancer aged 60.