Shinsaburo Tawata was taken off the active roster on April 29 because of tightness in his right shoulder. The condition is not considered serious, but he and might not be ready to return to the active roster until some time around the start of Inter-league play.
[UPDATE 5/20 @ 4:41pm]
Tawata threw about forty pitches to a standing catcher in the bullpen on May 19. It was his first session since his injury. He threw at about sixty percent.
Source: Sports Hochi 5/20/2017
[UPDATE 6/2 @ 11:41am]
Tawata could make his first rehab appearance during a three-game series against Ni-gun Yomiuri that begins on June 6.
Source: Sports Hochi 6/2/2017
[UPDATE 6/21 @ 12:23pm]
Pitching coach Yoshihiro Doi told reporters on June 20 that there were no problems with Tawata’s shoulder. He could return to the active roster in time for a Lotte game at Naha on June 28.
He has pitched in two rehab games at Ni-gun:
Source: Sponichi 6/20/2017