WALTHAM -- The Celtics hired NBA former point guard Tyronn Lue as their Director of Basketball Development on Friday. He will assist the coaching staff and observe practices. He made his debut on Friday in Waltham as the Celtics prepare for their season opener on Tuesday in Cleveland. Lue played 11 seasons with seven different teams, including last year with Orlando. The 32-year-old won NBA titles in 2000 and '01 with the Lakers. For more, visit the Green Street  blog.