Baltimore Orioles second baseman Jackson Holliday officially joined the MLB top prospect debut party, accompanying the likes of Milwaukee Brewers outfielder Jackson Chourio, and San Diego Padres outfielder Jackson Merrill. With Holliday, Chourio, and Merrill at the big-league level, they're currently the youngest players in MLB at 20 years or younger. With news of Holliday getting the call-up by the Orioles, the Baseball world has dubbed them the “Jackson 3.”