Sasaki's nickname is a tribute to legendary Japanese starting pitcher Daisuke Matsuzaka, who was known as the "Monster of the Heisei," referring to different eras of the Japanese calendar. The 23-year-old lost both his father and grandfather during the 2011 Tohoku earthquake and tsunami.

Prized Japanese pitcher Roki Sasaki says in an Instagram post he intends to sign with the World Series champion Los Angeles Dodgers.

The 23-year-old Japanese phenom has a fastball that regularly reaches triple digits and wowed MLB scouts at the World Baseball Classic in 2023.