Hirokazu Sawamura was taken off the active roster today. No specifics were mentioned by the Yomiuri Giants, but Yoshinobu Takahashi did tell reporters the pitcher was in no condition to pitch at the Ichi-gun level.
Sawamura was just added to the active roster on September 1. He did not pitch in any games during his three days on the roster.
[UPDATE 9/28 @ 11:28am]
Sawamura pitched in a Ni-gun game against Yakult on September 27. He entered the game in the sixth inning and did not allow a run or hit over an inning of work. He struck out one. This was his first game since August 29.
Source: Nikkan Sports 9/28/2017