With the MLB Postseason officially in full swing and the smack dab in the middle of the football season, one event in sports reigns supreme in the fall each year above all else:

…NBA Training Camp!

All joking aside, even the biggest of Celtics fans might not have realized Boston opened their training camp season on Tuesday at the Auerbach Center in Brighton, MA (there was a little baseball game happening in the Bronx that may have been distracting them).

The Celtics are entering the 2025-26 season in a position they haven’t been in in quite some time, and that’s as a true unknown as to what this team’s ceiling can be.

For the better part of a decade, Boston’s presumed ceiling has consistently been, at the very least, competing for an Eastern Conference title in May. And nestled in that fun, of course, have been rosters fully capable of winning it all.

But ladies and gentlemen, the 2024 Boston Celtics ain’t walking through that door.

On top of Jayson Tatum’s devastating Achilles rupture during Game 4 of the Eastern Conference Semifinals against the Knicks at Madison Square Garden likely knocking the five-time All-NBA forward for the entirety of the 2025-26 season, Boston saw the likes of Jrue Holiday and Kristaps Porzingis be moved this summer to get the team under the dreaded second apron to avoid steep luxury tax penalties. Additionally, future Hall of Fame center Al Horford has departed for a multi-year deal with the Warriors.

Add in the fact that this fall marks the beginning of the Bill Chisholm Era as the Celtics’ new majority owner, and it feels like this team went from a perennial title contender to an Eastern Conference middler seemingly overnight.

And if you don't believe me, I'll let the Vegas futures market do the talking, where OddsTrader lists the Celtics at +6600 to the win the 2026 NBA Finals via BetMGM as of publishing. The last time Boston's title odds were this low, they were heading into Brad Stevens' first season as head coach after trading Paul Pierce and Kevin Garnett to the Nets for the draft picks that eventually became Jaylen Brown and Tatum in consecutive years.

A lot, obviously, has changed since then. Stevens is now running the operation from a roster construction standpoint, faced with the new challenge of trying to effectively navigate this Tatum-injury holding pattern.

What can Brown do as a true, standalone No. 1 for this team? Is Derrick White capable of stepping up and being an All-Star-level offensive threat on a nightly basis? What will more minutes look like for Payton Pritchard? How will Boston’s new-look front court fare? Will new-comer Anfernee Simons thrive in the Joe Mazzulla three-point-heavy system? And how will the fourth-year head coach look without a bonafide wagon of a roster to work with for the first time in his young coaching career?

We have more questions than answers, which is what makes Boston’s training camp in particular so fascinating this year.

Here’s what happened on Celtics Training Camp, Day 1:

Jayson Tatum loomed large as a spectator

Last week, Tatum took part in a large 48-hour media junket, promoting both his new signature shoe with Jordan Brand as well as the pain medication Journavx. Throughout all of his interviews, as well as at Celtics Media Day, Tatum made it abundantly clear that he’s making great progress with his rehab, and that he wants to return to the court for regular season games as soon as humanly possible.

“I haven’t said I’m not playing this season,” Tatum said on ESPN. “The most important thing is a full recovery - not rushing it at all. But also, I don’t go to rehab six days a week for nothing.”

A few days later at media day, Tatum continued talking about his progress, in reference to a video of him already partaking in on-court activities.

"Getting back on the court and being able to participate in a basketball workout was one of the brighter spots in this journey," Tatum said. "It just felt really good to be on the court and dribbling the basketball, going through a workout, feeling like a basketball player again.

"I’m in a really good spot. It’ll be five months tomorrow, so how has it been? It's been a long journey."

With all of this said, Tatum was a mere spectator on Tuesday as the 2025-26 squad met for their first official day of camp. His presence on the sidelines loomed large, as his availability and recovery moving forward will in some form or another dictate every single decision this franchise makes over the next several years.

Come hell or high water, this man wants back on the court this season. Whether or not that makes sense for the organization long term is another topic for another day.

Fast Times at TD Garden

Something Boston’s new-look roster has been built around this offseason is the idea of a newfound uptempo offensive style this season after ranking 30th in the NBA in pace in 2024-25.

Without Tatum being the ball-stopper he is on offense (that’s no disrespect, it’s just how he plays), Boston is going to look to create more scoring opportunities earlier in the shot clock. Which, if you follow this team, should not come as a surprise, as Mazzulla once famously said early in his tenure in Boston that the most important stat in basketball is three-point attempt rate.

“You could tell right since I got here that that’s the focus this year,” new Celtics center Luka Garza told the media. “That what we want to do is get up and down and push the pace and get into actions early and be able to move the ball around and score and kind of use all sides of the floor while doing that.

“I think coach said today, we’re not just gonna play like that, we’re gonna practice like that. So, that was evident from the structure of the practice.”

Even with the Celtics playing slower than anyone else in the NBA last season, they were still among the league-leaders in offensive efficiency by almost every single metric. But when you have an All-World forward dictating the bulk of your scoring, you’re always going to be towards the top of this list regardless of how fast-or-slow you play.

But with Tatum out of the fold, this team is forced to find new ways to score.

“Think of a NASCAR pit stop where you just don’t stop moving,” forward Xavier Tillman told the media. “And it’s just like as soon as you go in, the guys are exchange, exchange and we’re out. That’s what it is. As soon as we cross half court we’re on it.”

The roster might look different, but expect the biggest change this season to be how this offense operates in a world sans Tatum.

A notable observer outside of Tatum

Former Grizzlies head coach Taylor Jenkins was a surprise observer on Tuesday, marking a rare public appearance for the 41-year-old after his shocking firing late last season.

“It was great to see him first and foremost,” said Tillman, who played for Jenkins in Memphis before being traded to Boston during the 2023-24 season. “I ain’t seen him since [Desmond Bane’s] wedding two summers ago, so it was great to see him.

“He was just here kind of seeing how we do things around here. He told me he’s taking the year off, so just spending a lot of time with his family. But he’s taken a couple times and opportunities to come check out other teams, see how they operate, see what he can take from their game and mold into his when he gets back into it.”

Mazzulla is famous for bringing other coaches into his building as a way to grow as a leader in his own right - from Manchester City coach Pep Guardiola to guys like Mike Vrabel and Alex Cora. And Mazzulla has been seen both at Patriots practice and Red Sox regular season games over the last few years, spending time with the coaching staff both on the sidelines and in meetings.

With his .539 winning percentage over six seasons down in Memphis, it’s no surprise Mazzulla would look to tap into some of Jenkins’ expertise as Boston looks to implement their new and improved run-and-gun style of play.

Tom Carroll is a contributor for Roundtable, with boots-on-the-ground coverage of all things Boston sports. He's a senior digital content producer for WEEI.com, and a native of Lincoln, RI.