Boston Celtics president of basketball operations Brad Stevens said the three-team trade that brought in Kristaps Porzingis but saw Marcus Smart head to the Memphis Grizzlies was all about balancing the team's roster.

"I said this at the start of the summer: I thought that we needed to balance our roster and make sure that we looked at the best ways to do that," Stevens told reporters early Friday morning after the NBA draft. "And that meant that we were going to likely lose a really, really, really good player."

Along with the Porzingis and Smart moves, the three-team trade between the Celtics, Grizzlies and Wizards sent forward Danilo Gallinari, center Mike Muscala and guard Tyus Jones to Washington and netted Boston a top-four-protected 2024 first-round pick. The Celtics also acquired the 25th overall selection in Thursday's draft, trading down multiple times before ultimately getting Arkansas' Jordan Walsh and a handful of future second-round picks.

Stevens said Porzingis will help the Celtics' offense and defense near the rim, adding that the 7-foot-3 center is "starting to play at the best level I've seen."

"From our standpoint, we just looked at it as 'what's our best opportunity to continue to grow and improve as a team?'" Stevens said. "Knowing that sometimes really, really hard decisions have to be made. Like I said, not only adding Kristaps with his skill, his size and the positional versatility, we just had many more numbers and options at the smaller positions than we did at the bigs, especially as we look forward too."

Stevens declined to address the initial three-team trade proposal that would have involved Malcolm Brogdon going to the LA Clippers. After that deal fell apart, the Celtics pivoted to talks with the Grizzlies to get a trade completed before Porzingis' deadline to opt in to his $36 million option for 2023-24.

Acquiring Porzingis was the first of several big decisions ahead for the Celtics this summer, as Boston can offer All-Star forward Jaylen Brown a five-year, $295 million contract extension and has to sort out the future of restricted free agent forward Grant Williams.

Boston will also have to adjust to life without Smart, one of the league's best and most versatile perimeter defenders who won the 2021-22 Defensive Player of the Year Award and has won the NBA's Hustle Award three times, including the past two seasons.

Stevens praised Smart, who had spent his nine-year NBA career in Boston after the Celtics drafted him No. 6 overall in 2014, for his contributions to the franchise.

"The greatest legacy that you can leave is to be someplace and it's better off because you were there," Stevens told reporters. "And I think that everybody here feels that way.

"I think that he will always be appreciated and thought of so fondly here for any number of reasons. Obviously, everybody loved the way that he plays and how hard he plays, but also his work in the community. You know, we're all really grateful to have Marcus in our life for as long as we've had and are sad to see him go."

Smart posted a goodbye to Boston in a tweet Friday, reflecting on his nine years with the organization.

"Where do I even begin...as I start to think about the last 9 years I have a lot of emotions running thru me," Smart wrote. "I came to Boston as a naïve kid from Dallas not really knowing what to expect. All I knew was the type of work ethic my momma instilled in me and I was going to work my ass off and make sure I EARNED the respect of each and every one of the fans in Boston. Which is why this was tuff.

"Boston, you are a very special place to me. I grew up here and met some of my best friends here. I'll never forget my time here. Ultimately we didn't get that 18th banner but I'm VERY VERY proud of the success we had. I'm going to miss so many things about Boston but mainly my teammates, fans, and kids and our hospital charity work. It was a great 9 years Boston, thank you for all the love...but now it's time to look forward."

Information from ESPN's Tim Bontemps was used in this report.