2021 MLB Draft - Top 600 Prospects — Prospects Live
2021 MLB Draft Scouting Report: SS Marcelo Mayer - Lookout Landing
Projecting the Top Fantasy Baseball Prospects in 2024: The Top-15 - FantraxHQ
2021 MLB Draft - Top 600 Prospects — Prospects Live
Red Sox draft top high school shortstop Marcelo Mayer with No. 4 pick
2021 Leaf Draft #41 Marcelo Mayer XRC RC Rookie RC Rookie Baseball Trading Card : Collectibles & Fine Art
MLB Draft 2021: A scouting report on Boston Red Sox pick Marcelo Mayer - Over the Monster
2021 MLB DRAFT SLEEPERS; Alex Mooney, Jaden Hill and more
MLB Draft 2021: Marcelo Mayer and Five Other Prospects to Watch - The New York Times
2021 MLB Draft - Top 600 Prospects — Prospects Live
2021 MLB Draft - Top 600 Prospects — Prospects Live
Marcelo Mayer drafted No. 4 by Red Sox in MLB Draft