Takashi Ogino hurt his left side during a game against Seibu at Seibu Prince Dome on April 27. He had trouble swinging the bat this morning and was taken off the active roster on the same day.
Source: Nikkan Sports 4/28/2016
[UDPATE 4/29 @ 3:10pm]
Ogino hurt his left side when throwing the ball during pre-game fielding practice on April 27. He was examined at a hospital in Tokyo on April 28 and diagnosed with a strain in his left internal oblique muscle. He will require four to six weeks for a full recovery.
Source: Sports Hochi 4/29/2016