BOSTON — The Boston Celtics’ rebuilding efforts took another major step on Thursday with the trade of the last remaining member of the team that won an NBA championship.

Boston sent point guard Rajon Rondo to Dallas on Thursday night, cutting ties with the last remnant of its 2007-08 title team while giving Dirk Nowitzki and the Mavericks a chance at another championship.

The Celtics confirmed that they will trade Rondo and forward Dwight Powell to Dallas for Jae Crowder, Brandan Wright, Jameer Nelson and two draft picks. The Celtics will also receive a $13 million trade exception, which they have one year to use.

“Welcome to Rajon Rondo the newest member of the Dallas Mavericks,” team owner Mark Cuban wrote on social media.

Boston will acquire 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, acquiring them in trades for Kevin Garnett and Paul Pierce and even coach Doc Rivers as it shed the pieces of the 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.”

Danny Ainge, the Celtics’ president of basketball operation, told WBZ-FM in Boston on Thursday before the trade was announced that his job is to make the team better, but in the past he has said he sees Rondo as part of the Celtics’ future.

“Listen, my job is to look at all the different ways and pathways for us to be a championship team,” Ainge said. “This is the time of the year that there’s a lot of talking and calling that’s going on.

“Part of my job is to explore the variety of ways there are to get us to our next championship. And that’s all we’re trying to do – just build a winner.”

When asked if the Celtics could move forward without Rondo, Ainge said, “I don’t know. That’s a good question. Rajon has been a big part of our team, not just this year but for the past years, as we know.

“We haven’t really seen what (rookie) Marcus Smart has been able to do yet because he hasn’t been healthy. He’s got such a shortage of minutes and opportunities to play with the ankle sprain. So it’s a good question. I don’t think any of us know the answer to that.”

Rondo, 28, joined the Celtics as the 21st overall pick out of Kentucky in 2006 and became the point guard for an NBA champion in his second year, after Boston acquired Ray Allen and Kevin Garnett. He helped the Celtics reach the NBA finals again two years later.

With the Celtics mired in what now looks to be an extended rebuilding process, Rondo became more valuable as a trading chip. Due to be a free agent at the end of the season, he was reportedly expecting a contract at or near the NBA maximum. Rondo has averaged 11 points, 8.5 assists and 4.7 rebounds over his career. He missed the second half of the 2012-13 season and the first half of last season to have reconstructive knee surgery, and then reportedly fell in the shower in Las Vegas on the eve of training camp and missed all of the preseason.

In 22 games this season for Boston, Rondo had an NBA-best 10.8 assists per game and also averaged 8.3 points and 7.5 rebounds. The feeling within the Mavericks, one source said, is that Rondo is the closest thing that’s available to the addition they got with Jason Kidd in 2007-08.

The Mavericks get a pass-first point guard – a four-time all-star – to team with Nowitzki, Monta Ellis and Chandler Parsons in what they hope will make them a contender again. Dallas is 19-8 this season but in third place in the Southwest Division behind Memphis and Houston, and sixth overall 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.

ESPN reported that the Los Angeles Lakers were also interested in Rondo and offered draft picks and point guard Steve Nash, who is injured and in the final year of his contract, to the Celtics. According to media reports, Houston and Sacramento were also interested.

In Wright, the Mavericks will be losing one of the most efficient players in the league. Wright is shooting better than 75 percent from the field.

Crowder was one of the Mavs’ best perimeter defenders and had found a niche within the rotation after being a second-round draftee two summers ago.

Nelson was brought in to be the starting point guard in Dallas and filled that role for most of the first third of the season. But he had not produced like the Mavericks had hoped, and a zero-point, zero-assist game in 25 minutes on Wednesday at Detroit may have convinced the Mavericks that this deal needed to get done.

Nelson signed a two-year, $5.5 million deal last summer after 10 seasons in Orlando. He is averaging 7.3 points and 4.1 assists while shooting 37 percent from the field.

One significant question for Dallas is whether Rondo, who makes nearly $13 million this season and is an unrestricted free agent next summer, will re-sign with the Mavericks long term.

Apparently, the Mavericks have received some level of assurance that Rondo will, indeed stay in Dallas.