During his spell at Highfield Road, John played his part in winning the Third Division title in 1964, but his playing days were limited after suffering a back problem and in 1966 he joined Plymouth Argyle, where he would eventually end his playing career.
During his spell at Highfield Road, Sillett played his part in winning the Third Division title in 1963-64, but his playing days were limited after suffering a back problem. In July 1966 Sillett joined Plymouth Argyle, where he would eventually end his playing career.