Joseph Phillip Cassidy (February 8, 1883 – March 25, 1906) was an American Major League Baseball player from Chester, Pennsylvania who mainly played shortstop for the Washington Senators from 1904 to 1905. He is the only player in American League history to record 19 triples in a rookie season. He was an alumnus of Villanova University.
Cassidy died in his hometown at age 23, from complications of malaria, and is interred at Immaculate Heart Cemetery.