 Cassidy joined the Providence Bruins of the AHL as an assistant coach in the 2008–09 season under head coach Rob Murray.Cassidy held this position for three years before being promoted to head coach of the team for the 2011–12 season after Murray was fired.During his first season as head coach, the club posted a 35–34–7 record, earning 77 points and failing to qualify for the playoffs.