Softbank Hawks manager Sadaharu Oh, the all-time home run king of Japanese baseball who guided Japan to the inaugural World Baseball Classic title in March, said Wednesday he will undergo surgery on a stomach tumor and temporarily leave his post.

News photo Fukuoka Softbank Hawks manager Sadaharu Oh talks to reporters at a press conference on Wednesday. KYODO PHOTO

Oh, 66, made the announcement after a game between Softbank and the Seibu Lions at Yahoo Dome, saying he will leave the Pacific League team Thursday and enter a hospital in Tokyo. Coach Hiroshi Moriwaki will steer the team as acting manager.

"I've been feeling discomfort in my stomach since about a week ago and an examination has found a tumor that requires surgery. I'm disappointed that I have to leave the team and baseball that I love in such a manner," Oh told reporters at a press conference.

"I believe the coaches and players will fight for the championship and hopefully I'll return to the team this fall," Oh said. "It's a shame that I don't have much more to say at this stage."

Oh holds the career home run record in Japan with 868 between 1959 and 1980 as a Yomiuri Giants player. He has managed the Hawks since 1995, after serving as Yomiuri manager from 1984 to 1988.

In March this year, he became the first manager to win the WBC with a team that featured major league players Ichiro Suzuki and Akinori Otsuka.