|Full name||Sidney William Cavendish|
|Date of birth||28 February 1876|
|Place of birth||Burton-on-Trent, England|
|Date of death||20 July 1954 (aged 77)|
|Place of death||Salisbury, England|
|* Senior club appearances and goals counted for the domestic league only.
† Appearances (Goals).
Cavendish was born in Burton-on-Trent and started his football career playing for nearby Overseal Town. In May 1898, he was spotted by a scout from Southern League champions, Southampton and he moved to the south coast, together with his team-mate, goalkeeper John Joyce.
Cavendish spent his first season at The Dell in the reserves, scoring 22 goals. His first-team debut came on 6 January 1900, when he took the place of the former England international Harry Wood at inside-left for the visit of Gravesend United. The "Saints" celebrated the start of the new century in style, with Cavendish scoring in a memorable 8–0 victory. Cavendish played in the next two matches (at centre-forward and centre-half respectively), before returning to the reserves.
Described as "a gentlemanly player, often winning esteem and respect from many of his opponents", Cavendish made only one appearance in the 1900–01 season, followed by five appearances in 1901–02.
In the 1902 close-season, Cavendish dropped into the Hampshire League with Freemantle before moving in 1904 to the East End of London with Clapton Orient. After a year in the Southern League Second Division when they finished in eighth position, Clapton Orient applied for election to the Football League and were successful, taking their place in Football League Division Two. Cavendish made no Football League appearances for Orient, although he did make one appearance in the FA Cup.
- Chalk, Gary; Holley, Duncan; Bull, David (2013). All the Saints: A Complete Players' Who's Who of Southampton FC. Hagiology Publishing. p. 39. ISBN 978-0-9926864-0-6.
- Holley, Duncan; Chalk, Gary (1992). The Alphabet of the Saints. ACL & Polar Publishing. p. 65. ISBN 0-9514862-3-3.
- Chalk, Gary; Holley, Duncan (1987). Saints – A complete record. Breedon Books. pp. 26–27. ISBN 0-907969-22-4.
- Saints – A complete record. pp. 28–29.
- Saints – A complete record. pp. 30–31.