Boston Red Sox shortstop Marcelo Mayer, who was taken with the fourth overall pick last year, was widely considered by scouts as both the best pure hitter and the best defender in the 2021 draft class. Mayer finished the 2021 season as MLB Pipeline's No. 9 overall prospect, and he's expected to be a top-five prospect heading into the 2023 season. The 19-year-old from Chula Vista, California, has a pure left-handed swing, generates plenty of contact and has an advanced approach at the plate. ...