Metallica [ tickets ] frontman James Hetfield had to sit out the band's last three shows due to a back injury, according to Metallica’s official tour website. Kid Rock [ tickets ] and Korn [ tickets ] singer Jonathan Davis--both of whose groups are touring with Metallica as part of the Summer Sanitarium Tour--as well as Metallica bassist Jason Newsted, filled in for the injured Hetfield.

The tour was scheduled to play at Atlanta’s Georgia Dome on Friday (7/7). Earlier that day, Metallica drummer Lars Ulrich reportedly told an Atlanta radio station that day that Hetfield had slipped a disc during a day off. Hetfield spent Friday night hospitalized, according to the band’s website.

Hetfield also had to sit out the band’s Saturday (7/8) performance in Sparta, Ky., and the Sunday (7/9) performance in Irving, Tx.

Concert-goers who attended any of the three shows Hetfield missed will be able to use their ticket stubs to attend a free make-up performance, according to the band’s website. The make-up dates for the three shows are: Aug. 2 in Columbus, Ohio, at Buckeye Lake (tickets issued for the Sparta, Ky., date will be honored here); Aug. 4 in Atlanta at the Georgia Dome; and Aug. 6 in Irving, Tx., at the Texas Stadium.

Set lists from the shows Hetfield missed that were posted on the band’s website credit Newsted with handling lead vocals on Metallica classics such as “Creeping Death,” “For Whom the Bell Tolls,” “Seek and Destroy” and “Whiplash.” Korn’s Davis took the mic for a rendition of Metallica’s “One,” while Kid Rock sang lead for a number of songs, including “Nothing Else Matters” and “Enter Sandman.” Rock and Newsted shared lead vocals on Metallica’s “Fuel” and a medley of Metallica’s “Sad But True” and Rock’s “American Bad Ass.” (Rock's recently released “American Bad Ass” features the music from “Sad But True” and a sample of Hetfield’s trademark yell.)

Representatives for Metallica could not be reached for comment on Hetfield’s condition. The Summer Sanitarium Tour’s next stop is scheduled for Wednesday night (7/12) in Denver.

Meanwhile, the venue for the Summer Sanitarium Tour’s July 16 stop--originally slated to take place at a fairground in Queen Creek, Ariz.--has been changed; that show will happen at Phoenix’s Blockbuster Desert Sky Pavilion.