The Allman Brothers Band closed a 10-night residency at the Beacon Theatre in New York City on Sunday night, and were forced to play parts of two of those shows without frontman and founder Gregg Allman. Allman walked off stage in pain on Saturday night and was taken to a local hospital.

TMZ reports that Allman was treated and released on Saturday. A statement at his Facebook page revealed more details. "For those who have asked - Gregg Allman has bulging discs in his back that are normally under control. Last night, he had a painful flare up 30 minutes before the end of the second set at the Beacon, which forced him to leave the stage."

Allman also missed Sunday night's show, but guest artists like John Popper, Jimmy Hall and Col. Bruce filled in. Jambands.com reports that Warren Haynes took over the remainder of the lead vocal duties.

On May 1, Allman will release a book called 'My Cross to Bear,' a memoir chronicling his battle with Hepatitis C. The virus often leads to liver inflammation, but still, the singer says he'll keep the tone light. “There’s been a few books that have come out about the Allman Brothers, so I thought if I ever do a book, I’m gonna stay on the funny side, because behind the scenes, it was hilarious.”