Tom Seaver, the Hall of Fame pitcher and former New York Mets great who helped the team win the 1969 World Series, has been diagnosed with dementia at age 74.

Seaver has retired from public life but will continue to work at the California vineyard he owns with his wife Nancy, his family announced Thursday. Seaver will not join his former teammates this season in New York to celebrate the 50th anniversary of the “Miracle” Mets who won that ’69 championship.

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The news of Seaver's illness saddened the baseball world, with former Mets and others sharing their admiration for the pitcher, who won a total of 311 games for the Mets, Cincinnati Reds, Chicago White Sox and Boston Red Sox in a career that stretched from 1967 to 1986.

“He will always be the heart and soul of the Mets, the standard which all Mets aspire to, this breaks my heart,” former Mets catcher Mike Piazza wrote in a tweet. “Do not feel worthy to be mentioned in the same breath.”

Seaver was diagnosed with Lyme disease in 1991 while he lived in Connecticut and it reoccurred in 2012 and led to Bell’s palsy and memory loss, the New York Daily News reported in 2013.

Seaver’s former teammate Art Shamsky revealed in an excerpt from his upcoming book “After the Miracle” that the pitcher was suffering from short-term memory loss. Bud Harrelson, another former teammate of Seaver’s, recalled telling teammates to be prepared when they meet with him.

“He can forget things that happened just a few minutes before,” Harrelson told Shamsky, according to Newsday. “And he repeats himself a lot. But when he gets his rest, he still has a lot of energy.”

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Seaver was a three-time NL Cy Young Award winner and the 1967 National League Rookie of the Year. He finished his career with 3,640 strikeouts and 61 shutouts. He was elected to the Hall of Fame where he received 98.8 percent of the vote – the highest percentage until Ken Griffey Jr. broke it in 2016.

The Associated Press contributed to this report.