Sasaki attended
Hanamaki Higashi High School in
Iwate Prefecture, and played for the school's baseball team. Sasaki set the Japanese high school record with 140
home runs. He graduated in March 2024. Sasaki decided to enroll at
Stanford University to play
college baseball for the
Stanford Cardinal rather than enter the
Nippon Professional Baseball draft. He arrived in time for the spring semester in 2024, but did not join the team for the 2024 season to acclimate to the United States. and for the
Greeneville Flyboys of the
Appalachian League in July. He debuted with the Cardinal in 2025.
Baseball America rated Sasaki as the best freshman in collegiate baseball before the season. He had a .269
batting average with seven home runs and 41
runs batted in in 52 games played for the Cardinal. After the 2025 collegiate season, Sasaki played
collegiate summer baseball for the
Cotuit Kettleers of the
Cape Cod Baseball League. He was eligible for the
2025 Nippon Professional Baseball draft and will be eligible for the
2026 Major League Baseball draft. On October 23, 2025, the
Fukuoka SoftBank Hawks and the
Yokohama DeNA BayStars selected him in the First Round of the NPB Draft, with the Hawks winning his negotiating rights. ==Personal life==