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