Complex sentence: At one point Lombardo rejected the possibility of a future "good-bye tour" for Slayer, and states if the band realize they have "lost a step" they will "call it a day".
Split into simpler sentences: At one point Lombardo rejected the possibility of a future "good-bye tour" for Slayer. If the band ever realizes they have "lost a step", he states they will simply "call it a day".