The Summer Sanitarium Tour was Metallica's packaged tour in the Summer of the year 2000. Taking place in "stadiums, arenas, and yes, even speedways," the tour was one of the top grossing tours of the Summer. It was also the final tour for long-time bassist Jason Newsted who quit the band in January 2001. Before the gig in Atlanta James Hetfield injured his back in a jet skiing accident and was forced to sit out three shows. Newsted sang most of the songs during these concerts, and the vocals and rhythm guitar were also taken by musicians from the supporting acts, such as Kid Rock and his guitarists Kenny Olson and Jason Krause, Serj Tankian and Daron Malakian of System of a Down, and Jonathan Davis of Korn. At the end of the tour Metallica played six make up shows, two for each show James missed.