Frank John Eustace
- Bats Unknown, Throws Unknown
- Height 5' 9", Weight 160 lb.
- Debut April 16, 1896
- Final Game June 21, 1896
- Born November 7, 1873 in New York, NY USA
- Died October 16, 1932 in North Manheim Township, PA USA
Frank Eustace was one of several players who got playing time at shortstop with the Louisville Colonels in 1896, on a team that didn't really settle on anybody that year. Eustace had 100 at-bats. General Stafford became the regular shortstop the following year with the team.