Complex sentence: After the 2010-11 season the Bears let go their longtime head coach and manager Bill Bowker and replaced him with the Ottawa 67's former assistant coach and assistant coach of the Bears during the 2010-11 season, Mark Grady.
Split into simpler sentences: After the 2010-11 season the Bears released their longtime head coach and manager Bill Bowker. Bowker was replaced with Ottawa 67's former assistant coach (and assistant coach of the Bears during the 2010-11 season) Mark Grady.