Jerry Koosman cause of death: Mets World Series legend dies at 83 after illness
The beloved pitcher who helped deliver the franchise's first World Series championship
Jerry Koosman , the former New York Mets pitcher whose performances helped deliver one of the greatest upsets in World Series history, has died at the age of 83 following a battle with multiple illnesses.
The two-time All-Star died on Sunday, November 1, in Osceola, Wisconsin, where he was surrounded by relatives. His death was confirmed by the Mets , bringing an end to the life of a player whose career became synonymous with the franchise's remarkable rise during the late 1960s.
Koosman was a central figure in the celebrated 'Miracle Mets' team that defeated the heavily favored Baltimore Orioles in the 1969 World Series, providing two crucial pitching performances as New York captured its first championship.
Longtime Mets executive Jay Horwitz announced the news, paying tribute to the left-hander's importance to one of baseball's most memorable championship teams.
"The 1969 Mets had a multitude of heroes, but no one was bigger than Jerry Koosman, who passed away this morning after battling multiple illnesses," Horwitz said.
Koosman 's death comes more than five decades after his finest achievements, although his contributions to the Mets continued to be celebrated long after his retirement.
What was Jerry Koosman's cause of death?
The Mets confirmed that Koosman had been dealing with several illnesses before his death, but the precise medical conditions involved have not been publicly identified.
Horwitz 's announcement provided the clearest explanation of the circumstances, while the organization confirmed that the former pitcher was with family in Wisconsin when he died.
Born in Appleton, Minnesota, Koosman joined the Mets in 1964 after attracting attention while pitching during his military service. He made his major league debut in 1967 before quickly establishing himself among baseball's most promising young pitchers.
His breakthrough arrived in 1968, when he recorded 19 victories and a 2.08 ERA, earning an All-Star selection and finishing second behind Johnny Bench in National League Rookie of the Year voting.
The following season, Koosman formed a formidable partnership with Tom Seaver as New York transformed itself from perennial underachievers into World Series champions.
Koosman's remarkable career and lasting Mets legacy
Koosman 's defining contribution came during the 1969 World Series, when he helped New York recover from an opening-game defeat against Baltimore.
He earned the victory in Game 2 before returning for the decisive Game 5, delivering another outstanding performance as the Mets completed their improbable championship triumph.
The left-hander spent 12 seasons with New York, winning 140 games and recording a 3.09 ERA before continuing his career with the Minnesota Twins, Chicago White Sox and Philadelphia Phillies .
His best individual campaign came in 1976, when he finished with a 21-10 record and placed second in National League Cy Young Award voting.
Across 19 major league seasons, Koosman accumulated 222 victories, 2,556 strikeouts and a 3.36 ERA before retiring in 1985.
The Mets inducted him into their Hall of Fame in 1989 and retired his No. 36 jersey in August 2021, cementing his place among the franchise's most influential figures.
His death leaves New York mourning a player whose contribution to the 1969 championship remains an enduring part of the Mets ' identity.
