 Armstrong hit two goals in 21 matches in the 1983–84 season as Vale were relegated out of the Third Division, despite an upturn in form under new boss John Rudge.Armstrong began to be plagued by a nagging knee injury, which required a cartilage operation.His injury kept him limited to just six appearances in the 1984–85 campaign, and he left the club on a free transfer to non-league Nuneaton Borough in May 1985, later moving on to Alliance Premier League rivals Northwich Victoria.