John P. Cassidy
- Bats Right, Throws Left
- Height 5' 8", Weight 168 lb.
- Debut April 24, 1875
- Final Game August 12, 1885
- Born 1857 in Brooklyn, NY USA
- Died July 2, 1891 in Brooklyn, NY USA
John Cassidy had one great season in an otherwise ordinary career. In 1877, at age 20, he hit .378/.386/.458 for the Hartford Dark Blues, their last season as a major league team. Cassidy's batting average was second in the league, his slugging percentage was third, and his Adjusted OPS+ was second behind Deacon White. Cassidy is also remembered for being a regular on the 1880 Troy Trojans, a team that featured five young Hall of Famers: Roger Connor, Dan Brouthers, Buck Ewing, Mickey Welch and Tim Keefe. John's line had slid hard that year, finishing .253/.277/.338. Mostly an outfielder, he also pitched 32 games, going 1-20 for the Brooklyn Atlantics in 1875.
In 1886, he became a politician and was elected to the Brooklyn Democratic General Committee. In 1887, it was said he was in business and no longer pursuing a baseball career.