Junichi Tazawa is a former Japanese professional baseball pitcher who played in the United States for the Boston Red Sox, Miami Marlins, and Los Angeles Angels. He began his career in Japan with the Nippon Oil ENEOS baseball team before being signed by the Red Sox in 2008.

Tazawa made his Major League Baseball debut in 2009 and quickly became a reliable reliever for the Red Sox. He was known for his fastball and splitter, which helped him strike out batters and induce ground balls. In his rookie season, Tazawa pitched in 37 games and had a 2.57 ERA.

Over the next few years, Tazawa continued to be a valuable member of the Red Sox bullpen. He pitched in over 60 games in both the 2012 and 2013 seasons and helped the team win the World Series in 2013. Tazawa pitched in six games during the postseason that year and did not allow a run.

In 2016, Tazawa signed with the Miami Marlins as a free agent. He struggled in his first season with the team, posting a 4.17 ERA in 55 games. However, he bounced back in 2017 and had a 4.15 ERA in 53 games.

Tazawa's final season in the majors was in 2018, when he played for the Los Angeles Angels. He struggled with injuries that year and only pitched in seven games before being released by the team.

Overall, Tazawa had a solid career in the majors. He pitched in 379 games and had a 4.12 ERA. He struck out 352 batters and had a 1.28 WHIP. While he was never a star player, Tazawa was a reliable reliever who could be counted on to get outs when needed.