Junichi Tazawa had been the constant in the Red Sox bullpen for the last five seasons, give or take. He was a career Red Sox reliever. Until now, as he is set to sign a free agent contract with the Marlins. Tazawa has had great strikeout-to-walk ratios throughout his career, but has struggled somewhat in the last couple of seasons.
After pitching in six games in his debut season in 2009, including the only four starts of his career, Tazawa underwent Tommy John surgery. He came back strong, after a brief stint back with the Red Sox in 2011. In 2012 he made it to Boston's bullpen to stay and had a terrific season. He was 1-1 with a 1.43 ERA and struck out 45 while walking just five in 44 innings. He also picked up his first save. His WHIP was an extremely impressive 0.955.
The 2013 season saw Tazawa emerge as the team's primary setup man. His ERA rose to 3.16 and his WHIP to 1.200, but he struck out 72 and only walked 12 in 68.1 innings. Tazawa also saw his only postseason experience to date and appeared in 13 games. He picked up a win in the ALCS against the Tigers and only gave up one earned run across his appearances while striking out six and walking one.
In 2014, Tazawa had his best full season. He was 4-3 with a 2.86 ERA in 71 games. He struck out 64 and walked 17 in 63 innings. He struggled in 2015, going 2-7 with a 4.14 ERA but his strikeout-to-walk ratio improved from the prior season. He spent a brief amount of time as the closer and notched three saves. Finally, in 2016 he finished 3-2 with a 4.17 ERA. He was not as reliable and ended up getting shut down for rest.
Junichi Tazawa has been one of the more underrated heroes of the Red Sox for the last several seasons. He has been a major part of the team's bullpen for the last half decade but never really seemed to get the attention he deserved. For his career with the Red Sox, Tazawa was 17-20 with a 3.58 ERA and four saves. He has struck out 308 and walked just 71 in 312 innings. Tazawa will be missed, though this was not unexpected.