The Boston Red Sox selected Guerrero out of Chipola College in the 17th round, with the 496th overall selection, of the 2021 Major League Baseball draft. He made his professional debut in 2022, and split the season between the rookie–level Florida Complex League Red Sox, Single–A Salem Red Sox, and High–A Greenville Drive. In 27 total appearances, Guerrero accumulated a 4–5 record and 3.23 ERA with 59 strikeouts and 9 saves in 39.0 innings of work.
In 2023, Guerrero was assigned to the Double–A Portland Sea Dogs to begin the year.On June 30, 2023, Guerrero was selected to play in the All-Star Futures Game, replacing teammate Shane Drohan, who was sidelined with a calf ailment. In September, Guerrero was recognized as the Red Sox' minor-league reliever of the year for 2023. On the season, he posted a 1.81 ERA with 59 strikeouts and 18 saves in 43 relief appearances for Double–A Portland prior to his promotion. In 6 appearances for the Triple–A Worcester Red Sox, he posted a 7.71 ERA with 9 strikeouts and one save in 4+2⁄3 innings of work