Hall of Fame pitcher Tom Seaver has been diagnosed with dementia and will retire from public life, his family announced on Thursday.

In a statement released by the Hall of Fame, Seaver's family expressed thanks to those who have supported the New York Mets great throughout his career and asked for privacy.

Seaver, 74, helped propel the Miracle Mets of 1969 to a World Series title. The right-hander, known as "Tom Terrific," won the Cy Young Award that year and led the National League with 25 wins.

The Mets, who retired Seaver's No. 41 in 1988, are celebrating the 1969 team on June 29. They released a statement on Thursday saying they plan to honor Seaver, even though he will not be able to attend the ceremonies.

Statement from Jeff Wilpon on behalf of ownership and the Mets organization on Tom Seaver. pic.twitter.com/LozVvDR27T — New York Mets (@Mets) March 7, 2019

Seaver has limited his public appearances in recent years. He did not attend the Baseball Writers' Association of America dinner in January where members of the 1969 team were honored on the 50th anniversary of what still ranks among baseball's most unexpected champions.

Several of his former teammates reacted to the news Thursday.

Ed Kranepool, Seaver's teammate on the 1969 Mets, told the Bergen Record, "He always handled himself with dignity and class. My wife Monica and I have the Seavers in our prayers."

Ron Swoboda, another member of that team, said, "Nobody competed like Tom Seaver. I was proud to be his teammate."

Another Met in the Baseball Hall of Fame, Mike Piazza, posted on social media, "He will always be the heart and soul of the Mets, the standard which all Mets aspire to."

Tom Seaver recorded 311 wins, 3,640 strikeouts, 61 shutouts and a 2.86 ERA during his 20-year career. Louis Requena/MLB Photos via Getty Images

Piazza, whose career did not overlap with Seavers', added: "This breaks my heart. Do not feel worthy to be mentioned in the same breath, yet honored to be with him in the Baseball Hall of Fame."

A star at the University of Southern California, Seaver was drafted by Atlanta in 1966 and signed with the Braves only for baseball commissioner William Eckert to void the deal because the Trojans already had played exhibition games that year; baseball rules at the time prohibited a club from signing a college player whose season had started. Any team willing to match the Braves' signing bonus could enter a lottery, and the Mets won out over Cleveland and Philadelphia.

Seaver, the 1967 Rookie of the Year, was selected to the All-Star Game 12 times, led the league in strikeouts five times and won three Cy Young Awards. He finished his career with 311 wins and 3,640 strikeouts.

He also pitched for the Cincinnati Reds and Chicago White Sox and finished his 20-year career with the Boston Red Sox in 1986. Seaver was a first-ballot Hall of Famer in 1992, receiving 98.8 percent of the vote.

Seaver's family says he will continue to work at Seaver Vineyards, founded by the retired player and his wife, Nancy, in 2002 on 116 acres at Diamond Mountain in the Calistoga region of California.

The Associated Press contributed to this report.