Yomiuri Giants pitcher and former major leaguer Koji Uehara, who won the World Series with the Boston Red Sox in 2013, announced Monday that his career is over.

“I want to end my 21-year baseball career today,” Uehara, told a press conference in Tokyo. “There is a part of me that wants to play on, but I decided from the beginning (of the season) that this is my last.”

The 44-year-old right-hander, who made his professional debut with the Giants in 1999 and rejoined the team in March last year, said he has been unable to put in solid performances this season.

“I thought the first three months of the season were crucial. I was feeling very conflicted because I wasn’t called up to the top team and at the same time I was unable to play well at the farm team,” he said with tears in his eyes.

In addition to his World Series title in 2013, Uehara had stints in the big leagues with the Baltimore Orioles, Texas Rangers and Chicago Cubs.

After rejoining Yomiuri last year, Uehara went 0-5 with a 3.63 ERA in 36 games, but hasn’t appeared with the first team this season. He underwent surgery on his left knee last autumn and was released after the season. He later agreed on a new contract with the team, making him the oldest player with a current NPB deal.

Uehara was the CL’s 1999 rookie of the year, and won the Sawamura Award that season as Japan’s most impressive starting pitcher, posting 20 wins.

He won the Sawamura Award again in 2002, finishing 17-5 with a 2.60 ERA.

Over a 10-year span, he was 112-62 with 33 saves before moving to the U.S. as a free agent in 2009.

Uehara spent time with the Orioles and Rangers before finding a more permanent home with the Red Sox from 2013 to 2016.

In 2013, he posted 21 saves and a 1.09 ERA. He was named the that season’s American League Championship Series MVP before going on to help the Red Sox win the World Series.

Uehara pitched in five of the six games for Boston in that year’s World Series matchup against the St. Louis Cardinals, including closing the final game of the series by pitching a perfect ninth inning at Fenway Park.

Uehara joined the Cubs for the 2017 season. He pitched in 49 games for Chicago going 3-4 with a pair of saves and a 3.98 ERA.

He did not appear in the postseason and was released after that campaign.

In the major leagues, Uehara has a career record of 22-26, with 95 saves and a 2.66 ERA

Uehara was 112-67 with a 3.02 ERA overall in Japan. He helped the Giants win the Japan Series in 2002 and was an All-Star during the 1999 and 2002 seasons.