A year ago, the Boston Celtics stood tall as the reigning NBA champions, sparking discussions about how many additional titles their formidable lineup might secure. The future seemed bright for the Celtics’ core, brimming with potential and promise.

Fast forward to today, and the landscape has dramatically shifted. The once-dominant core has largely been dismantled. The Celtics find themselves grappling with the aftermath of a second-round playoff exit at the hands of the Knicks. Suddenly, they’re no longer seen as frontrunners for the NBA Finals, a stark reminder of how swiftly fortunes can change in the NBA.

This rapid transformation is precisely what makes the start of each NBA season so exhilarating. With every new season comes a whirlwind of roster changes, unexpected team ascensions, and, regrettably, injuries that can alter the league’s dynamics. For fans, it’s an invitation to strap in and enjoy the rollercoaster ride over the next eight months.

As the 2025-26 regular season prepares to tip off on Tuesday night, there are several key narratives to keep an eye on. The Eastern Conference, in particular, presents a tantalizing opportunity. The Celtics are currently without Jayson Tatum, and the Indiana Pacers will be missing Tyrese Haliburton, both sidelined due to Achilles injuries. This opens the door for new contenders to step up and seize their moment.

Before the 2025-26 regular season officially tips off on Tuesday night, here are 10 things to watch for.

BEAST OF THE EAST

The Eastern Conference is there for the taking, as the Celtics are missing Jayson Tatum and the Indiana Pacers are without Tyrese Haliburton as both recover from Achilles tears.

The window is wide open for the Knicks, who hired Mike Brown to replace Tom Thibodeau as head coach and revamped their bench after their run the 2025 conference finals.

But the Cleveland Cavaliers, who went 64-18 as the East’s No. 1 seed last season, remain squarely in the mix, while up-and-coming teams such as the Orlando Magic and Detroit Pistons could take a leap.

GIANNIS WATCH

After an offseason of trade rumors, Giannis Antetokounmpo is back with the Milwaukee Bucks, but his future appears murkier than ever.

That’s because ESPN recently reported Antetokounmpo eyed the Knicks as a possible destination, and that the Knicks and Bucks even discussed what a trade might look like.

“I’m here. I believe in this team. I believe in my teammates,” Antetokounmpo said a day after that report.

“Now, if in six, seven months, I change my mind, I think that’s human too, you’re allowed to make any decision you want, but I’m locked in. I’m locked in to this team. I’m locked in to these guys, to this group and to this coaching staff and to myself.”

Milwaukee, which released a rehabbing Damian Lillard (Achilles) and signed center Myles Turner this offseason, will need to exceed expectations to avoid a fourth consecutive first-round exit or worse.

THUNDER STORM

The Oklahoma City Thunder are in about as enviable of a position as a team can be, bringing back basically the same roster that just won the NBA Finals.

OKC is again the favorite, but the NBA has not featured a repeat champion since 2017-18.

Maintaining continuity is difficult in this era of salary aprons and player mobility, and even though Shai Gilgeous-Alexander, Jalen Williams and Chet Holmgren are signed long-term, the Thunder have a prime opportunity to strike again now while their depth remains intact.

But it won’t be easy in the wild, wild West.

ROCKET LAUNCH

Speaking of the West, all eyes are on the Houston Rocket after they pushed their chips in and traded for Kevin Durant this summer.

Durant joins a Houston team that claimed the West’s No. 2 seed behind a young cast including Alperen Sengun, Amen Thompson and Jabari Smith Jr. But the Rockets already suffered a blow this offseason when veteran point guard Fred VanVleet went down with an ACL tear.

That puts a greater emphasis on 21-year-old guard Reed Sheppard, who was the No. 3 overall pick in the 2024 draft but averaged only 4.4 points and 12.6 minutes per game as a rookie.

LAKE SHOW

LeBron James and Luka Doncic showed flashes of what that pairing is capable of after the Los Angeles Lakers acquired the latter in a stunning midseason trade, but an otherwise depleted roster led to a first-round playoff exit.

And while the Lakers didn’t do much to retool over the summer — De’Andre Ayton and Marcus Smart were their biggest additions — it will be interesting to see what a full season of James and Doncic looks like.

It will be similarly interesting to see if this ends up being the 40-year-old James’ final season.

RAISE THE FLAGG

There are mulligans, and then there’s the stroke of divine intervention the basketball gods awarded the Dallas Mavericks after they traded Doncic away.

The Mavs landed the No. 1 pick in the draft and used it on another generational prospect in do-it-all forward Cooper Flagg.

Dallas may not contend right away as point guard Kyrie Irving rehabs from a torn ACL, but when he returns, a core of Flagg, Anthony Davis, Irving, Dereck Lively and Klay Thompson looks quite formidable.

From a development standpoint, the 18-year-old Flagg could benefit as he handles some of the Mavs’ play-making duties in Irving’s absence.

SPURS SURGE

Completing the NBA’s Texas three-step are the San Antonio Spurs, who many expect to take a major leap in Victor Wembanyama’s third season.

Wembanyama, 21, is apparently still growing, as the Spurs website now says he’s 7-4 after listing him at 7-3 last year.

And Wemby is set to play with the best supporting cast of his career, with No. 2 overall pick Dylan Harper joining a group of guards that includes reigning Rookie of the Year Stephon Castle and 2023 All-Star De’Aaron Fox.

CELTICS RESET

The Celtics parted with Jrue Holiday, Kristaps Porzingis and Al Horford this offseason for salary-cap relief, while Tatum is expected to miss most, if not all, of the upcoming season.

Boston could still compete for a lower seed or a play-in spot with Jaylen Brown, Derrick White and Payton Pritchard, but the bigger question is how the Celtics will position themselves for another run in the future.

It’s at least somewhat surprising Anfernee Simons, on an expiring contract, will begin the year on the Celtics, but the high-scoring guard could still be a mid-season trade chip after coming to Boston in the deal that sent Holiday to Portland.

PHILLY SPECIAL

Perhaps no team faces more pressure than the Philadelphia 76ers, who spiraled to a 24-58 record during last season’s disaster.

All of that losing netted the Sixers a building block in rookie VJ Edgecombe to pair with Tyrese Maxey in the backcourt, and Philly hopes Joel Embiid (knee) is finally healthy after missing all but 19 games last season.

But between Embiid’s contract and that of Paul George, the Sixers won’t have much flexibility to make changes should this plummet into another lost season.

DENVER DO-OVER

It was notable this offseason that Nikola Jokic bypassed the chance to sign a four-year, $212 million extension, and the three-time NBA MVP remains tight-lipped about whether he intends to sign an even bigger deal next summer.

But the Denver Nuggets brass made it a point to surround Jokic with a superior supporting cast, bringing in Cam Johnson, Bruce Brown and Jonas Valanciunas while sending Michael Porter Jr. to Brooklyn.

The Nuggets are not far removed from their 2022 championship, and they took OKC to seven games in the second round last year.

But if Denver fails to make progress for a third year in a row, expect more speculation about Jokic’s future.