Takashi Saito (45) has decided that this will be his last season. He is scheduled to hold a press conference in Sendai to formally announce his decision on August 17.
Saito turned forty-five earlier this year in February. He has struggled with his conditioning and has only managed to pitch in two Ichi-gun games this season. His last game came against Ni-gu Yakult on August 6: he entered the game in the 9th, gave up two runs on three hits and two walks, and topped out at 144km/h.
Source: Sports Hochi 8/17/2015, Nikkan Sports 8/17/2015, Sponichi 8/17/2015
[UPDATE 8/18 @ 12:29am]
The Eagles held a press conference for Saito on August 17.
On why he decided to retire:
There wasn't just one reason. There were a number of reasons. The reality of not being able to help the team at a time like this, my performance that hasn't been good enough. For a lot of reasons, I felt like this was the time for me to step away. I can't recalled a specific at bat, moment on the mound, or hitter I was facing. I think there's no doubt that the decision slowly came to me.
On when he decided:
Just two weeks. When I thought about where the team was and where I was, I found the reason to quit. I feel the answer came to me quite simply.
On what he has planned:
I want a little time to relax. Then may be around September, help out with practices and do a little training myself.
On the possibility of a retirement ceremony:
The organization told me they want to hold one. It's something we have to talk about and then I'll let them handle it.
Source: official announcement, Nikkan Sports 8/17/2015