The Guardians selected De Los Santos during the 2023 Rule 5 Draft on Wednesday.
The 20-year-old was at Double-A Amarillo with the Diamondbacks last season and had a .254/.297/.431 slash line with 20 homers in 113 games. De Los Santos will skip the Triple-A level with Cleveland, and will need to stay on the big-league roster for all of 2024 in order for the organization to retain him.