More than a week ago, the 22-year-old right-hander from Japan decided to sign with the Red Sox after also receiving overtures from the Rangers, Braves, Mariners and perhaps some other teams.
Only some final logistics -- such as Tazawa flying from Japan to Boston and taking his physical -- held up the official announcement.
Tazawa landed in Boston at roughly 11:45 p.m. ET Monday night and spent the past couple of days getting acclimated and taking care of administrative stuff.
Today, he will get to elaborate to the media on his reasons for choosing to bypass the Japan pro draft and go straight to a Major League franchise.
It was an unusual step in that nearly all of the recent Japanese players who have come to the United States -- from Ichiro Suzuki to Hideki Matsui to Boston's duo of Daisuke Matsuzaka and Hideki Okajima -- had prolonged pro careers in Japan before making the move.
Tazawa is near certain to begin his time with the Red Sox in the Minor Leagues. However, he will be able to spend Spring Training working in-depth with Matsuzaka and Okajima, which should help him both from a pitching and cultural standpoint.
The Boston Globe recently reported that Tazawa's contract -- a Major League deal which will put him on the 40-man roster -- is for three years at $3 million.
Thursday's news conference will mark the first time the Red Sox have discussed Tazawa in dealings with the media.
His fastball is said to frequent the low 90s and some reports also indicate that Tazawa has a solid forkball and slider.
In 2008, Tazawa pitched for Nippon Oil of the Japan Industrial League, which is for amateur players only. He dominated in that league, finishing his season with a complete-game shutout on Nov. 21.
Ian Browne is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.