Legendary knuckleball pitcher Phil Niekro died Sunday, the Baseball Hall of Fame announced. He was 81.

Niekro was a five-time All-Star and five-time Gold Glove winner. He played 24 years in the major leagues from 1964 to 1987. He spent 21 years with the Atlanta Braves and also played for the New York Yankees, Cleveland Indians and Toronto Blue Jays.

"Phil Niekro’s record on the field ranks him as one of the game’s finest pitchers," National Baseball Hall of Fame and Museum Chairman Jane Forbes Clark said in a news release. "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. On behalf of the Board of Directors and the staff of the National Baseball Hall of Fame, I would like to send our heartfelt condolences to Nancy Niekro and the Niekro family."

Niekro was 48 years old when he retired from the majors. He finished up in 1987 with the Braves.

He won 268 games, recorded 2,912 strikeouts and recorded a 3.20 ERA during his pitching days. He pitched in 4,622.1 innings and had 226 complete games. He topped the 300-inning mark in four seasons with the Braves.

Niekro was known for perfecting the knuckleball pitch, which helped elevate his pitching game. Legendary New York Yankees player Bobby Murcer said trying to hit Niekro was like "trying to eat Jell-O with chopsticks."

"(My father) taught it to me in the backyard," Niekro previously said. "I didn’t know what it was or anything, he showed me how to hold it and we’d just play knuckleball in the backyard."

He was elected into the Baseball Hall of Fame in 1997. His brother, Joe, also had a solid major league career.