Since the Cavaliers won their first NBA title back on June 19, NBA teams have undergone a number of changes over the long summer offseason. NBA.com's Shaun Powell will evaluate the state of each franchise -- from the team with the worst regular-season record in 2015-16 to the team with the best regular-season record -- during the month of September as we look at 30 Teams in 30 Days. | Complete schedule

Today's team: Boston Celtics

2015-16 record: 48-34

Who's gone: F/C Jared Sullinger, G/F Evan Turner

Who's new: SF Jaylen Brown, PF Guerschon Yabusele, C Ante Zizic, PG Demetrius Jackson, PF Ben Bentil, SF Abdel Nader (via Draft); G Gerald Green, F/C Al Horford (via free agency)

The lowdown: The Celtics finished two wins shy of 50 last season and continued to show progress under the coach-GM combo of Brad Stevens and Danny Ainge.

These are bountiful times in Beantown when it comes to the C's, who remain devoid of a superstar but are confident that teamwork and hard work will send them to the playoffs again. And who knows, maybe they'll play deep into May.

The shine on the franchise was blinding enough this summer to fetch the attention of one of the better free agents on the market: Horford. In their glorious past, the Celtics won championships mainly with talent that was home-grown or imported through Auerbachian trades. This was a source of pride for the Celtics, although the other avenue in which to build a roster -- free agency -- wasn't as successful.

There were theories; some cited weather and a checkered racial history for the city of Boston. On that latter note, the Celtics have always stood in the forefront of racial progress; they suited up the first black NBA player (Chuck Cooper) and made KC Jones the first black NBA coach (following Bill Russell's stint as player-coach). That said, the perception of the Celtics as a team that favored white players to appease the fans was faulty. What team wouldn't have Larry Bird and Kevin McHale and Hondo Havlicek?

Anyway, all of that was moot when the Celtics signed Horford away from Atlanta, where he spent his entire career. Horford is a four-time All-Star, a consistent big man known for his work ethic near the rim and mid-range jumper from the elbow. He was applauded in Atlanta for his professionalism and low maintenance, which should reflect well in a far more rabid basketball town like Boston.

To be clear, Horford wasn't Plan A. The Celtics went hard after Kevin Durant, who was impressed but went to the Warriors instead. Still, the Celtics got an interview with a once-in-a-lifetime free agent, so you must like their chances on the market in the future.

The Stevens-Ainge brain trust is considered one of the better combos and suddenly Boston is a destination place. The team is on the up-swing and Ainge has assets, not only on the roster but he controls the next two No. 1 picks from the rebuilding Nets.

He used the Nets' No. 1 this year, which was fourth overall, on Brown, which was met with some skepticism. Did Ainge maximize this golden asset, or was Brown a fallback option? In a perfect world, Ainge would've swapped the pick along with a few roster players for a proven talent, but a DeMarcus Cousins-like deal never materialized. In addition, some questioned Ainge's decision to draft Brown ahead of Kris Dunn, Jamal Murray and Buddy Hield.

But Ainge liked Brown's high motor and athletic ability and figured the rookie, who's only 19, will eventually sharpen his shooting accuracy and tone down mistakes. Plus, unlike the others, Brown at 6-foot-7 can play comfortably at the swing positions.

Brown will likely see minutes initially at small forward where there's a vacancy in the rotation. The Celtics didn't push hard to re-sign Turner, who took his mid-range, all-around game to Portland. Turner had an encouraging season in Boston and showcased himself well, but after signing Horford, Boston wasn't ready to write more big checks for a player they thought was replaceable.

The Celtics renounced their qualifying offer to Sullinger, setting him free, but did extend a two-year, $16 million contract to Tyler Zeller, a role-playing big man. That meant Zeller will be the team's fourth-highest-paid player, ahead of Jae Crowder and Isaiah Thomas, who inked their deals a few years before the salary boom and make just over $6 million a season.

This raises a fair question: Will jealousy over money infect the locker room? Horford will make $20 million more this season than Thomas, who's locked into his deal at least until next summer, when he can re-negotiate. Crowder's deal has at least two more years to run.

Winning cures everything, and the Celtics are built to do that, barring injury. With few exceptions, their players can play more than one position, which gives Stevens a handful of lineup options, depending on the opponent.

Signing Horford only added to that mix, and he should be a boost to a team seemingly headed in the right direction. For anyone looking for a candidate in the East that answers only to the Cavaliers, the Celtics must be under strong consideration.

Coming Next: Charlotte Hornets

To check out the rest of the series schedule, click here.

Veteran NBA writer Shaun Powell has worked for newspapers and other publications for more than 25 years. You can e-mail him here or follow him onTwitter.

The views on this page do not necessarily reflect the views of the NBA, its clubs or Turner Broadcasting.