A “backache” had Mayor Gavin Newsom sidelined from a public appearance Thursday, though he did go to work at City Hall.

A former college baseball player, Newsom, 40, threw his back out playing in the celebrity softball game during Major League Baseball’s All-Star Game week last year. His injury Thursday appeared to be a recurrence of his previous back injury, said Nathan Ballard, his spokesman, who dubbed it a “backache.”

It was not revealed how the mayor injured his back again. During the celebrity game, the left-handed mayor did not get a hit, flying out to former San Francisco 49er Jerry Rice, but he did play a solid first base.

dsmith@examiner.com