The media learned on October 2 that thirty-three-year-old Kentaro Nishimura is planning to retire. An announcement and press conference is expected some time within the next few days.
Nishimura struggled with right elbow problems and had two surgeries earlier in his career, one in 2009 and another in 2015. He also bounced back and forth between the bullpen and starting rotation and pitched in a career-high seventy-one games in 2013.
Nishimura suffered a dislocated right shoulder earlier this year in July. He decided to retire because he was not making sufficient progress in his rehab.
[UPDATE 10/4 @ 12:55am]
Nishimura held a press conference at the Giants’ offices in Otemachi on October 3. He told reporters he decided to retire because he was not sure if he would be able to pitch next year after he dislocated his shoulder earlier this year in July. He also told reporters he had no regrets because he was able to win his share of championships and titles over his fifteen-year career.
Source: Yomiuri 10/3/2018