Yokohama BayStars closer Kazuhiro Sasaki underwent endoscopic surgery to clean joints in his right knee on Tuesday and will be hospitalized for four to five days, baseball sources said.
Sasaki, who was removed from the active roster April 22, a day after blowing his third save this season, is expected to resume light pitching in about two weeks when he will be allowed to play catch.
"I told him to take as much time as he needs to recover. I don't want to set a timetable for his return because that would put pressure on Sasaki," said BayStars manager Kazuhiko Ushijima.
The 37-year-old right-hander, who left the Seattle Mariners in January 2004 to restart his career in Japan, is 0-3 with four saves with a 9.53 ERA in eight games this season. He also had surgery on his pitching elbow last fall. With a 650 million yen annual salary, Sasaki is the highest-paid Japanese baseball player in history.