

Jack William Ralston (born August 13, 1997) is an American professional baseball pitcher for the Miami Marlins of Major League Baseball (MLB). He made his MLB debut in 2026.
Amateur career
Ralston attended William S. Hart High School in Newhall, California, where he played baseball and had a 1.16 earned run average (ERA) as a junior in 2014 and a 2.06 ERA with 72 strikeouts as a senior in 2015.
During the summer of 2015, Ralston played for the La Crosse Loggers of the Northwoods League. He was redshirted as a freshman at the University of California, Los Angeles (UCLA) in 2016, and then returned to the Loggers that summer. He also did not appear in a game for UCLA in 2017, although he did once again play collegiate summer baseball that summer, this time with the Chico Heat of the Great West League. Ralston made his first appearance with UCLA in 2018. He pitched in 14 games (nine starts) and had a 1–4 win-loss record, a 6.44 ERA, and 18 strikeouts across 36+1⁄3 innings pitched. During the summer of 2018, he played in the Cape Cod Baseball League with the Wareham Gatemen. With UCLA in 2019, Ralston had an 11–1 record with a 2.66 ERA across 17 starts.
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