Niekro made five All-Star teams throughout his career, winning more than 300 games.
Phil Niekro, the master of the knuckleball, died overnight at the age of 81, the Baseball Hall of Fame and Museum announced on Sunday.
No official cause of death was released.
“Phil Niekro’s record on the field ranks him as one of the game’s finest pitchers,” Jane Forbes Clark, chairman of the National Baseball Hall of Fame and Museum, said in an official statement. “As a mentor, leader and friend, Phil brought out the best in all of us in Cooperstown."
Niekro's career spanned more than two decades and saw the knuckleball specialist make five All-Star teams and win more than 300 games. He spent 21 years with the Atlanta Braves, where he developed into a true workhorse, at one point logging more than 330 innings in three consecutive seasons.
He won 121 games after turning 40, and retired with 318 victories over the course of 5,404 innings—the fourth-most all-time and the most of any pitcher whose career started in the live ball era.
"But even more than his signature pitch and trademark durability, Phil will be remembered as one of our game's most genial people," MLB commissioner Rob Manfred said in a statement. "He always represented his sport extraordinarily well, and he will be deeply missed."
Niekro, along with his brother, Joe, who died in 2006, also hold the record for the most victories by a brother combination with 539.
He was inducted into the Baseball Hall of Fame in 1997 and served on the Museum's Board of Directors since 2009.
He is the fourth Hall of Fame pitcher to die in 2020, along with Tom Seaver, Bob Gibson and Whitey Ford. Hall of Fame second base manJoe Morgan and outfielders Al Kaline and Lou Brock also passed away this year.
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