His first at-bat resulted in the solo shot in the second inning of the contest. The Tokushima Indigo Socks won the Shikoku Island League game 3-2.
Ramirez is the team's designated hitter. He has played 11 games for Kochi, according to the Japan Times.
Ramirez, 44, was a 12-time All-Star, nine-time Silver Slugger winner, a batting title champion, and a two-time World Series winner in 19 seasons. After spending the first eight years of his career with the Cleveland Indians, he joined the Red Sox. Ramirez joined the Los Angeles Dodgers in 2008 and made big-league appearances with the Chicago White Sox and Tampa Bay Rays. He also played in the minor leagues for the Oakland Athletics, Texas Rangers and Chicago Cubs.
"Man-Ram" made more than $206 million in salary during his playing career.
Ramirez had 555 home runs and owned a .312 batting average during his decorated big-league tenure.
No. 99 signed with Kochi in February. His contract includes a personal driver in a Mercedes, a hotel suite, unlimited sushi and optional practices.
Kochi battles Tokushima again at 6 p.m. Thursday at JA Bank Tokushima Stadium.
An authentic Ramirez Fighting Dogs jersey is available for 19,500 yen or $170 on the team's website.