OAKLAND >> Rickey Henderson, the Oakland kid who became the greatest leadoff hitter in baseball history and his hometown A’s biggest star, has died.

Henderson would have turned 66 on Christmas Day.

After a frenzy of social media speculation overnight, multiple sources confirmed to the Bay Area News Group on Saturday morning that Henderson had died. The family is expected to make an announcement later in the day. Henderson had been in the hospital battling pneumonia, a source told the Bay Area News Group.

The left fielder with the unmistakable crouched batting stance and affable swagger set MLB career records with 2,295 runs and 1,406 stolen bases and is the single-season stolen base king. He was enshrined into the Hall of Fame in 2009, his first year of eligibility.

“My favorite hero was Muhammad Ali,” Henderson said during his induction speech in Cooperstown, New York. “He said one time, quote, I am the greatest, end of quote. That was something I always wanted to be, and now that the (Baseball Writers’ Association of America) has voted me into the Baseball Hall of Fame, my journey as a player is complete. I am now in the class of the greatest players of all time, and at this moment, I am very, very humbled.”

Henderson played for the A’s in parts of 14 seasons over four different stints during his 25-year career and he is considered the greatest player in Oakland franchise history.

News of his death is another emotional blow to A’s fans whose team is leaving Oakland after 57 seasons. They are headed to West Sacramento before, if all goes according to plan, relocating permanently in Las Vegas. Former franchise stars Sal Bando, Ken Holtzman and Vida Blue also died since January 2023. It was just six months ago that Willie Mays, the greatest player in the history of the cross-bay San Francisco Giants, died at the age of 93.

Rickey Nelson Henley Henderson was born in Chicago in the back seat of an Oldsmobile before his mother could get to the hospital. He often joked of his arrival that Christmas Day in 1958 that, “I was already fast.”

Henderson’s family relocated to Oakland, where he became a star athlete at Oakland Technical High. Another often-shared story was that Henderson, a high school All-American running back, dreamed of playing for Oakland’s other team — the Raiders. But his mother, Bobbie, persuaded him to turn to the baseball diamond because he was less likely to get hurt.

Despite his trademark headfirst slides, Henderson played a quarter-century in the majors and mostly avoided serious injury. Only Pete Rose, Carl Yastrzemski and Hank Aaron played more games in the majors than Henderson.

“I guess Mom do knows best,” Henderson noted during his induction speech. “Thanks, Mom.”

The Oakland A’s drafted Henderson in the fourth round of the 1976 draft, just as the Swingin’ A’s who won three straight World Series titles from 1972-74 were being broken up.

In 1979, the A’s lost more than 100 games for the first time since it arrived from Kansas City 11 years earlier.

But that was also the year Henderson arrived, and became a fan favorite.

Henderson was just 20 when he made his major league debut with Oakland on June 24, getting two hits in four at-bats, along with his first career stolen base. He batted .274 as a rookie and stole 33 bases in 89 games.

All of that was just an appetizer.

In 1980, Henderson became the first player in the history of the American League to steal 100 bases in a season. Two years later he stole 130 bases, breaking Lou Brock’s MLB record of 118 set in 1974.

Henderson led the American League in stolen bases 12 times, including in 1998 when, at the age of 39, he stole 66 bases with the A’s. Henderson also had power to go with his speed, hitting 297 career home runs, including a MLB-record 81 to lead off a game.

Henderson played for nine different franchises during his career, but always had a home with the A’s in Oakland. In 2017, the playing surface at the Coliseum was dedicated as Rickey Henderson Field.

“Growing up in Oakland as a kid, playing in the parks around the ballpark, I had no idea that this chance would ever come,” he told reporters at the dedication ceremony. “The first thing was getting the opportunity to play for the Oakland A’s and being from Oakland, and now this has happened. So it’s a special, great moment.”

Henderson and fellow Oakland star Dave Stewart threw out simultaneous ceremonial first pitches before the A’s final game at the Coliseum on Sept. 26.