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.”