Complex sentence: The band's original bassist, Justin Meacham, left the band in 2000 to replace Avenged Sevenfold's original bassist Matt Wendt, and was replaced by Chris Maurer, the younger brother of former lead vocalist Tim Maurer.
Split into simpler sentences: The band's original bassist, Justin Meacham, left the band in 2000 to join Avenged Sevenfold and replace their original bassist Matt Wendt. He was soon replaced by Chris Maurer, the younger brother of former lead vocalist Tim Maurer.