Tom Seaver, an American baseball pitcher who played 20 seasons in Major League Baseball and won 311 games, most notably the Mets, passed away on Monday at the age of 75.

The cause of his death was complications of Lewy Body Dementia (LBD) and COVID-19, according to the Baseball Hall of Fame.

At 6-foot-1 and 200 pounds, give or take a few, with a thick waist and tree-trunk legs that helped generate the velocity on his fastball and hard slider and the spin on his curveball, Seaver at work was a picture of kinetic grace. He had a smooth windup, a leg kick with his left knee raised high, and a stride so long after pushing off the mound that his right knee often grazed the dirt.

Apart from being one of the best pitchers, Seaver was a cerebral sort, a thinker who studied opposing hitters and pored over the details of each pitch.

Seaver played for the Cincinnati Reds, the Chicago White Sox, and the Boston Red Sox during the second half of his career.

He was the team’s first bona fide star, known to New York fans as “Tom Terrific” and “The Franchise.”

Until his arrival, no pitcher in the Mets had ever won more than 13 games in a season. Seaver won 16 games in his first year and 16 more in the next year.

Seaver was the league’s rookie of the year in 1967. He was an All-Star nine times in 10 full seasons with the Mets. He even won three Cy Young Awards as the league’s best pitcher.

In 1970, the Mets catcher Jerry Grote told Sport magazine, “He [Seaver] was a heck of a lot responsible for tightening things up around here. From the first year, he was going out to win, not pitch his turn. When Seaver’s pitching, those guys plain work a little harder.”

Since 1969, Seaver was a celebrity and part of a new generation of sports heroes in New York. He starred with Joe Namath of the Jets, who won the Super Bowl nine months before the Mets earned their championship.

Seaver, who was studying dentistry, was the best pitcher on U.S.C.’s roster. He was later drafted by the Dodgers.

MLB Commissioner Ron Manfred called Seaver “one of the greatest pitchers of all time.” He said, “After their improbable World Series Championship, Tom became a household name to baseball fans – a responsibility he carried out with distinction throughout his life.”