Jack Dempsey Cassini (October 26, 1919 – September 20, 2010) was an American professional baseball infielder, manager and scout.

[1] Cassini threw and batted right-handed, stood 5'10" (1.78 m) tall and weighed 175 pounds (79 kg).

His career began with the Tiffin Mud Hens of the Class D Ohio State League in 1940, where he batted .396 and stole 51 bases in only 99 games.

[1] In 1949, he received his only trial in Major League Baseball as a pinch runner in eight games for the Pittsburgh Pirates.

Cassini then fashioned a long career as a minor league manager and MLB scout.