Tomoyuki Sugano did not participate in team practices at Tokyo Dome on October 6. He showed up at the stadium around 13:10 and then left abou ten minutes later. There is a chance he might not be able to start Game 1 of the First Stage of the Climax Series. Yoshinobu Takahashi and other members of the coaching staff avoided divulging information about the situation.
[UPDATE 10/7 @ 4:32pm]
The Giants have not made any official announcements, but the media is assuming Sugano left practices early because he was not feeling well.
[UPDATE 10/8 @ 12:46am]
Sugano did not participate in practices on October 7.
Source: Daily Sports 10/7/2016
[UPDATE 10/8 @ 10:05pm]
Sugano joined the Ichi-gun team for practices at Tokyo Dome on October 8.
Source: Nikkan Sports 10/8/2016