The Boston Celtics traded point guard Rajon Rondo to Dallas on Thursday, cutting ties with the last remnant of their last NBA championship while giving Dirk Nowitzki and the Mavericks a chance at another title.The Celtics will send Rondo and forward Dwight Powell to Dallas for Jameer Nelson, Jae Crowder, Brandan Wright, two draft picks and a $12.9 million trade exception.Boston got a first-round pick in next year's draft and a second-rounder in 2016. The Celtics have eight first-round picks in the next four years, picking them up in trades for Kevin Garnett and Paul Pierce and even coach Doc Rivers as they shed the pieces of the New Big Three that earned the franchise its unprecedented 17th NBA title in 2008."We would not have won Banner 17 without Rajon and will always consider him one of our most valuable Celtics," the team's owners said in a joint statement. "We will always cherish the time he was here."The Mavericks get a pass-first point guard a four-time all-star to team with Nowitzki, Monta Ellis, Chandler Parsons and Tyson Chandler in what they hope will make them a contender again. Dallas is 19-8 this season but in third place in the Southwest Division and sixth in the Western Conference.The Mavericks, who won their only NBA title in 2011, have not won a playoff series since.The deal has been years in the making, with the Celtics shopping Rondo every time a coach grows tired of his moods or his contract expectations grow too large for their budget. But every previous time Boston management decided that the offers weren't enough.Celtics general manager Danny Ainge found a partner in Dallas, which is coached by his former Boston teammate Rick Carlisle.