Fukuoka Softbank Hawks pitchers Daisuke Matsuzaka and Kenji Otonari will be lost for the rest of the season, the club said Tuesday.
Matsuzaka had arthroscopic surgery on his right shoulder and will begin rehabilitation after being discharged. He is expected to need six months to make a full recovery.
Matsuzaka, who failed to make the opening-day roster due to flu, was diagnosed with soreness in the shoulder on April 2 and had been trying to work his way back.
"Making a quick decision allows you to put it behind you," Hawks manager Kimiyasu Kudosaid Tuesday. "If it allows you to pitch without anxiety next year, then that's the best thing."
The left-handed Otonari has also decided to undergo the knife soon on his pitching elbow.
The 31-year-old was one of Softbank's second-half stars last season upon his return from 2013 back surgery. He is 5-4 this season with a 2.54 ERA. He also had elbow surgery in October 2008.
"If he makes a decision soon, that will help next season," Kudo said. "I don't think it's a bad idea."
Matsuzaka signed a three-year, ¥1.2 billion deal plus incentives with the Japan Series champions in the offseason, but has not made a single start for them in his return to Japanese baseball after nine years in the major leagues.
The former Boston Red Sox pitcher started for the farm team on May 20, allowing a run in two innings of work but was scratched from his next scheduled start due to discomfort in the shoulder.
Matsuzaka played for the New York Mets last season.