UPDATE: Metallica Frontman Forced To Sit Out Shows

Metallica's James Hetfield was forced to sit out three of the band's concerts over the weekend after aggravating a chronic back injury prior to a Friday night gig at Atlanta's Georgia Dome.

According to Atlanta radio station WNNX, which spoke with drummer Lars Ulrich at the venue on Friday, Hetfield slipped a disc during one of the band's off days from its headlining stint on the Summer Sanitarium tour, which had last played on July 4 in Baltimore.

Newsted opened all the shows by belting out "Creeping Death," "For Whom The Bell Tolls," and "Seek And Destroy," and the bassist hooked up with Kid Rock to duet on "Fuel" and a rendition of Creedence Clearwater Revival's "Fortunate Son" during the Kentucky performance.

Metallica plans to perform make-up shows in the three cities after the completion of the Summer Sanitarium tour on July 16 in Queen Creek, Arizona. The Atlanta date has been rescheduled for August 4, while the new Irving, Texas gig will be held

on August 6.

The Sparta, Kentucky make-up date will take place in another venue, as it is now booked for the Buckeye Lake Music Center in Columbus, Ohio on August 2.

Management reps for Metallica told MTV News that Hetfield is currently receiving treatment for a bulging disc and a herniated disc by a doctor and specialist in Denver. The frontman is expected to rejoin the band in time for its July 12 concert at Mile High Stadium.

While Hetfield will be seeking relief, Ulrich will be seeking congressional help in Metallica's continued fight against Napster during a visit to Washington, D.C. on Tuesday.

While there, Ulrich will testify before a U.S. Senate Judiciary subcommittee about Napster and other MP3 file-swapping aids.

For a glimpse inside the Summer Sanitarium tour, including exclusive interviews with and footage of Metallica, Korn, Kid Rock, Powerman 5000, and System Of A Down, be sure to tune into the MTV special "All Access: Metallica"

airing on July 22.