Baseball Hall of Famer Phil Niekro, who retired at the age of 48 before baffling big-league hitters with his signature knuckleball for more than two decades, mostly with the Atlanta Braves, died after a long fight with cancer, the team announced on Sunday. He was 81.

The Braves said Niekro died Saturday night in his sleep. He lived in the suburb of Flowery Branch, about 45 miles northeast of Atlanta, where the main thoroughfare bears his name.

Niekro won 318 games over his 24-year career, which ended in 1987 after he made one final start with the Braves.

Known for a knuckleball that was actually thrown with just two fingernails, Niekro didn’t even know where it was going before he emerged as a five-time All-Star who had three 20-win seasons with Atlanta.

Niekro also pitched for the New York Yankees, Cleveland Indians and Toronto Blue Jays late in his career.

We are heartbroken on the passing of our treasured friend, the Braves said in a statement, reported by the New York Times. 

Nicknamed Knucksie, Niekro was woven into the Braves fabric, first in Milwaukee and then in Atlanta. Phil was always the first to join in community and fan activities where he would communicate with fans as if they were long lost friends.

A statue of Niekro delivering his trademark pitch is located outside of Truist Park, the Braves’ stadium.

Niekro didn’t make it to the big leagues until 1964, when he pitched 10 games in relief for the then-Milwaukee Braves.

He finally blossomed as a starter in 1967 the Braves’ second year in Atlanta when he went 11-9 and led the National League with a 1.87 ERA.

With a fluttering pitch that required catchers to wear an oversized mitt, Niekro went 23-13 as the Braves won the first NL West title in 1969.

He also had 20-win seasons in 1974 and 1979, despite pitching for a team that fell on hard times after its appearance in the inaugural NL Championship Series, where the Braves were swept in three games by New York’s Amazin’ Mets.

He finished with a career record of 318-274 and a 3.35 earned run average. Later, Niekro was inducted into the Baseball Hall of Fame in 1997.

His younger brother, Joe, also had a long baseball career with an arsenal that included the knuckleball. He won 221 games over 22 years in the big leagues.

Niekro and his brother, Joe — who died in 2006 at age 61— own the record for victories among siblings with 539, just ahead of Gaylord and Jim Perry.