Jason Newsted is credited with bass on Metallica’s self-titled 1991 album, commonly called The Black Album.
Newsted joined Metallica in 1986 after the death of bassist Cliff Burton. He had already appeared on the band’s 1987 extended play The $5.98 E.P.—Garage Days Re-Revisited and on …And Justice for All before playing on The Black Album.
The 1991 record gave the bass guitar a more audible role than many listeners associated with …And Justice for All. Producer Bob Rock encouraged a fuller low-end sound, and Newsted’s playing became part of the album’s heavier, more polished production. The standard album credits list him as bassist.
Robert Trujillo was not yet a member of Metallica when the album was recorded; he joined the band in 2003. Cliff Burton had died years earlier, while Ron McGovney had left Metallica before the band’s debut album. Those timeline differences explain why the credited bassist is Newsted.