Complex sentence: Cliff Martinez was hired as the band's new drummer while Martinez's bandmate in The Weirdos, guitarist, Dix Denney was expected to replace Slovak however after a few rehearsals the band felt he didn't fit and auditions continued.
Split into simpler sentences: Cliff Martinez was hired as the band's new drummer and Martinez's band mate in The Weirdos, guitarist, Dix Denney was expected to replace Slovak. After a few rehearsals, however, the band felt he didn't fit and auditions continued.