Carrasco of the Fukuoka SoftBank Hawks, and became the fifth NPB player drafted out of high school to hit a grand slam in his first season.

He had a resurgent season in 2011, posting a .218/.244/.265 slash line with 2 home runs and 22 RBI in 122 games, and earned his first career NPB All-Star selection.

The following season, Sumitani played in 104 games for Seibu, posting a .251/.289/.348 slash line with 5 home runs and 30 RBI.

In 2018, Sumitani played in 47 games for the team, logging a .248/.265/.310 batting line with no home runs and 9 RBI on the year.

On July 4, 2021, Sumitani was traded to the Tohoku Rakuten Golden Eagles in exchange for cash considerations.