Iwakuma underwent arthroscopic surgery on his right shoulder Friday and will resume throwing in five months. That timetable would have Iwakuma beginning his rehabilitation right around the start of spring training. As such, it isn't guaranteed that the 36-year-old will be healthy and ready to go by the start of next season.
Mariners' Hisashi Iwakuma: Undergoes arthroscopic shoulder surgery
CBS Sports | Sep 30