Justin Prinstein (born February 4, 1984), nicknamed "Boomer", is an American former professional baseball player, coach, and scout. He played in the Israel Baseball League in 2007 and other international leagues before becoming a scout in 2013.
Playing career Prinstein played college baseball for Albion College then the George Washington Colonials and continued as a professional in Belgium, Israel, Australia and the Netherlands. In 2007, he pitched a no-hitter in his first professional start with the Hoboken Pioneers in Belgium and then moved on to the sole season of the Israel Baseball League (IBL), pitching for the Netanya Tigers. He was named to the North All-Star team as a pitcher, and hit .318 as a designated hitter during the second half of the season.
Prinstein played winter ball in Adelaide, Australia, for Southern Districts in the South Australia Baseball League, where he was a teammate of Adam Crabb, a fellow IBL All-Star for Tel Aviv Lightning.
In 2008, Prinstein pitched for the in the Dutch First Division. The following season, in 2009, Prinstein signed as starting pitcher for Almere'90 in the Netherlands. The team won promotion following a five-game final, with Prinstein getting the win in relief of Game 5. In 2010, he returned to Almere to pitch in the Hoofdklasse.
Prinstein transferred to the Hamburg Stealers in the German Bundesliga for the last two weekends of the 2010 season (2 starts, 1–1 record), helping the club reach the playoffs, where he was ineligible to pitch due to the late transfer. He returned to Hamburg the following summer but was released after the first half of the season.
In the 2009–2010 winter, Prinstein pitched for the West Stirling Indians in the Western Australian state league competition, with a 1–9 record in 11 starts.
In addition to his playing career, Prinstein has coached with the Hungary national team beginning in 2011. In 2012, he became head coach, and was a Coach of the Year finalist in the European Baseball Coaches Association voting. Connected to his work in Hungary, he has supported the Janossomorja Rascals of the Hungarian league as a coach and player, helping them to multiple Hungarian League final appearances and Hungarian Cup championships between 2010 and 2013.
Prinstein was head coach and a starting pitcher of in the Czech Extraliga in 2013. He ended his playing career in 2014.
Scouting career Prinstein has worked as a Major League Baseball (MLB) scout for multiple clubs in Europe and became an international scout for the Baltimore Orioles in 2013. He also scouted for the Houston Astros. In 2020, he was a scout for the Cincinnati Reds. He was with the Reds until 2023.
In December 2025, Prinstein was hired by the Los Angeles Angels. He was fired by the Angels after recording a Colorado Rockies coach on his cell phone in June 2026.
Personal life Prinstein is an alumnus of University of Detroit Law School and a relative of Olympic gold medalist track and field athlete Myer Prinstein.
References