(CNN) Baseball Hall of Fame pitcher Phil Niekro has died at the age of 81 after a battle with cancer, the Atlanta Braves announced on Sunday.
"We are heartbroken on the passing of our treasured friend, Phil Niekro," the Braves said in a statement. "'Knucksie' was woven into the Braves fabric, first in Milwaukee and then in Atlanta. Phil baffled batters on the field and later was always the first to join in our community activities. It was during those community and fan activities where he would communicate with fans as if they were long lost friends."
After a 24-year career spanning from 1964 to 1987, Niekro was inducted into the National Baseball Hall of Fame in 1997.
Niekro mastered the art of throwing the knuckleball, a rarity among major league pitchers, which earned him the nickname "Knucksie."
"The goal of a knuckleball is to eliminate almost all of the spin on the baseball, causing it to flutter unpredictably on its way to the plate," MLB.com says. Knuckleballs are difficult for batters to hit -- and catchers to catch -- because of the ball's erratic movement, MLB.com said.
For two decades, Niekro anchored the Braves' starting rotation in both Milwaukee and Atlanta. Niekro's 740 games pitched in a Braves uniform is still the franchise record. Over his major league career, he won 318 games, lost 274 and had a 3.35 earned run average.
"Phil Niekro was one of the most distinctive and memorable pitchers of his generation," MLB Commissioner Rob Manfred said in a statement. "In the last century, no pitcher threw more than Phil's 5,404 innings. His knuckleball led him to five All-Star selections, three 20-win seasons for the Atlanta Braves, the 300-win club, and ultimately, to Cooperstown."
Manfred added, "But even more than his signature pitch and trademark durability, Phil will be remembered as one of our game's most genial people. He always represented his sport extraordinarily well, and he will be deeply missed. On behalf of Major League Baseball, I extend my condolences to Phil's family, friends and the many fans he earned throughout his life in our National Pastime."
"Phil Niekro's record on the field ranks him as one of the game's finest pitchers," said Jane Forbes Clark, chairwoman of the National Baseball Hall of Fame and Museum. "As a mentor, leader and friend, Phil brought out the best in all of us in Cooperstown. Over more than a decade of serving as a Member of the Board of Directors of the Hall of Fame, his wisdom, his compassion, and his love for the game proved to be invaluable in helping us shape our decisions."
Niekro is survived by his wife Nancy; sons Philip, John, and Michael; and his two grandchildren, Chase and Emma.