James Duncan was a Scottish footballer who played for Sheffield United as an outside left^[1] Signed in 1889, he had answered United's advert in the Scottish press asking for players to form a club, playing regularly for the Bramall Lane side for their inaugural season which consisted mainly of friendly fixtures.^[1]

At the end of the first season it was suggested that he had returned to Scotland along with several of his team-mates. In December 1891 however he began to feature for The Blades once more, playing a number of games between then and the end of that season, although only making two league appearances.^[1] During the following summer the local press reported that he had again returned North of the border but the club continued to list him as a player, retaining his registration for another year, despite him making no further appearances.^[1]