Complex sentence: Vicious joined the Sex Pistols in early 1977 to replace Glen Matlock; since his skills on bass guitar were highly questionable he only performed on one song on the band's sole studio album, "Never Mind the Bollocks".
Split into simpler sentences: Vicious joined the Sex Pistols in early 1977 to replace Glen Matlock. Since his skills on bass guitar were highly questionable, Vicious only performed on one song on the band's sole studio album "Never Mind the Bollocks".