Tristan Thompson spent each of his first nine seasons with the Cavaliers, becoming the ultimate energy guy and a key starter on the 2016 championship team.

Now, Thompson is officially a member of the Boston Celtics, a squad that enters the 2020-21 season as a legitimate contender.

That signing became official Monday, and the Cavs felt compelled to give Thompson a proper goodbye.

“Tristan Thompson represented the Cavaliers and the city of Cleveland with the utmost grace and class during his nine seasons in Northeast Ohio,” the Cavs said in a statement. “Tristan embodied everything a franchise would want in a player during his time as a Cavalier.”

The statement continued.

“He became a champion, a mentor and a great community partner through his selfless acts off the basketball court,” it read. “Affectionately recognized for his durability, competitive spirit and determination, Tristan was an integral part of our four consecutive NBA Finals trips, culminating in the franchise’s first-ever NBA Championship in 2016. We thank Tristan and wish him nothing but the best, knowing that he has earned a place in the hearts of Cavaliers fans and this organization forever.”

Thompson entered the offseason as an unrestricted free agent. After the Cavs acquired center Andre Drummond at the February trade deadline, there were immediate doubts about Thompson’s return.

Those doubts became reality earlier this month, when it was reported that Thompson would signa two-year deal worth about $19.9 million with the Celtics.

Interestingly, the best game of Thompson’s career came last season against Drummond, when Drummond was still with the Detroit Pistons. Thompson recorded a career-high 35 points and grabbed 15 rebounds in the Cavs’ 115-112 overtime road win.

Welcome to Boston @Teague0 and @RealTristan13 ☘️☘️

📝: https://t.co/GVlyJMriL7 pic.twitter.com/439TtgYQ1K

— Boston Celtics (@celtics) November 30, 2020

He ended the season with averages of 12.0 points and 10.1 rebounds, serving as a strong voice of leadership when times got tough. But for as assertive as Thompson could be with his younger teammates, he was also someone who could lighten the mood and keep spirits high.

He also spoke the truth with the media.

Now, he will move into a similar role alongside talents such as Celtics wings Jayson Tatum and Jaylen Brown, and point guard Kemba Walker. He will now be coached by Brad Stevens.

Thompson should fit right in — just as he did alongside one-time Cavaliers stars LeBron James and Kyrie Irving, as well as Kevin Love. Now, Love and recently re-signed veteran Matthew Dellavedova are the lone two remaining members of the championship team.

But as the Cavs indicated in their statement, Thompson’s contributions to that accomplishment will live on franchise lore.