John Cassidy
- Given Name
- John P.
- Born
- 1855 — Brooklyn, NY, USA
- Died
- 7/3/1891 — Brooklyn, NY, USA
- Weight
- 168 lbs
- Height
- 5' 8"
- Throws
- L
- Bats
- R
- Team(s)
- Brooklyn Atlantics (1875–1884)New Haven Elm Citys (1875)Hartford Dark Blues (1876–1877)Chicago White Stockings (1878)Troy Trojans (1879–1882)Providence Grays (1883)Brooklyn Grays (1885)
- Debut
- 1875-04-24
- Final Game
- 1885-08-12
20-Loss Season
1875 · Brooklyn AtlanticsW1L21ERA3.03WHIP1.381