WITH JUST A few days before the start of the regular season -- and as the Boston Celtics were still coming to grips with an offseason full of roster turnover that continued right up to the start of training camp -- Jayson Tatum decided it was time to have a conversation.

The Celtics had, just a few weeks earlier, acquired Jrue Holiday the day before camp opened Oct. 3, bringing in one of the league's best two-way guards who had been a pillar of Boston's biggest rival in the Eastern Conference, the Milwaukee Bucks.

But while Boston celebrated his arrival, he brought with him plenty of questions. The Celtics had spent the summer planning to use a clear starting five: Tatum, Jaylen Brown, Al Horford, Derrick White and Kristaps Porzingis, who came to the Celtics in the first massive move of the team's summer back in June.

With Holiday now in the fold, the Celtics had six starting-quality players -- and only five spots to put them in, meaning one of them wouldn't be introduced as a starter, and one would be sitting on the pine in the closing minutes of games.

Both topics quickly were injected into the bloodstream in Boston, with plenty of fans and those in the media opining about how it should go. But rather than letting it fester, and allowing one of the league's biggest unanswered questions to spiral into a narrative, Tatum gathered his five teammates in a room at the team's practice facility -- without any coaches, or anyone else. He wanted to address the obvious elephant in the room.

"I wanted us to get in the room and talk about it," Tatum told ESPN. "We all are human and have feelings, and I opened the floor and basically said, 'There's six of us. Only five can play at one time. One of us is not going to finish the game all the time.

"Whether it's fair or not, me and JB are probably going to always start, and always finish the game. But we have to be held to a different standard and be able to be coached differently. Whether it's KP and Al, one of you guys may not finish a game, and you have to be OK with that."

Boston is an Eastern Conference-leading 11-3 heading into Wednesday's showdown with Holiday's old team, the Bucks, in Boston (7:30 p.m., ESPN), the first of potentially 11 meetings this season between the Eastern Conference heavyweights.

No one inside that room believes the player meeting is the sole reason for their torrid start. But everyone involved does believe it will pay dividends beyond the clarity of purpose it provided in the early going: It should, they believe, help the team do what it has failed to do throughout the Jayson Tatum Era: raise Banner 18 to the TD Garden rafters.

"I think, honestly, it was a very important moment for us," Porzingis told ESPN. "Just to kind of look each other in the eye, and know that we're here for one job, and to understand that we're all going to be willing to make some sacrifices.

"SACRIFICE" IS A word that is often thrown around in NBA circles -- especially among teams with multiple superstars. Some teams and players have the leaders and veterans to embrace it. Some others preach the exercise but don't practice it. Others wilt under the pressure.

Tatum, now in his seventh year, has seen all three. And, when those six players sat down together before the season began, it wasn't lost on anyone that Holiday -- the one player in the room who has won an NBA championship, and played a key role in the Bucks doing so two years ago -- made it clear his approach would be the same regardless of how the lineup decisions shook out.

That included whether he would start, he said, or come off the bench -- a debate that raged in the media around the Celtics throughout the preseason.

"I've just been really impressed with [Holiday's] commitment to the team, to what we're trying to do," Horford told ESPN. "You can already tell he's a no-excuse type of guy. It's a lot, what he's had to go through and relocation and getting used to a new environment, and we're asking a lot of him."

Coach Joe Mazzulla ultimately opted to start Holiday and shift Horford to the bench, creating a starting five of Tatum, Brown, White, Holiday and Porzingis that, in 176 minutes across 10 games together has posted a 9-1 record and is outscoring teams by 28.4 points per 100 possessions -- easily the best 5-man group in the NBA to date. But what mattered more to everyone in the room was Holiday's approach -- and offer.

"I came out of that meeting, and my respect for him grew tremendously," Porzingis said. "And I told him right away.

"His demeanor in that meeting ... he said it, and he meant it, and we knew that he meant it. And being an NBA champion and just having all that experience and coming into a new team, one of the biggest rivals, and just being like that ... that also just set the standard for everybody else in that meeting.

"Man," he concluded with a smile, "Top G. Top dude."

Holiday, for his part, said the meeting helped him feel comfortable as the newest member of a team built to compete.

"It means a lot," he told ESPN. "Even just knowing that we had it early, we had it before the season started. We didn't have to figure this out later on, or let it linger and kind of keep it under the rug.

"It was good to have it at the time we had it."

FOR ANYONE WHO was unaware of how important Horford is to the Boston Celtics, even as he's playing in his 17th NBA season, look no further than the game a week ago in Philadelphia.

With Porzingis missing his first game of the season with a knee bruise, Horford slid right back into the starting lineup, squaring off against Joel Embiid -- the NBA's MVP and a player whom Horford has constantly bedeviled throughout his career (even including the one season they played together, a disastrous experiment that helped set the stage for Horford's return to Boston).

The fact Horford had a terrific individual performance -- 14 points on 5-for-9 shooting, including 4-for-8 from 3, along with 8 rebounds, 3 assists, 5 blocks and no turnovers - showed how impactful he can be on the court. But it was only a precursor to how his coaches and teammates spoke about him afterward.

Mazzulla: "It's the most inspiring thing for me as a coach is to watch him ... he's one of the most selfless, humble people that you have."

Tatum: "He's the ultimate professional, the ultimate team guy. He does whatever we need him to do on a nightly basis to win, and we all believe in him and the work that he puts in."

White: "Al is amazing. Everything he does out there I'm just thankful to be his teammate, just seeing the work he puts in day in and day out, it's inspiring. You see why he's played for 17 [seasons] now."

Ultimately, it was Horford who sacrificed, sliding to the bench, after he had done so in only 12 games (10 in regular season, two in playoffs) across the first 16 seasons of his NBA career.

Tatum has openly talked about the impact Horford has had on him. And he said their relationship was a significant factor in wanting to get everyone in a room before the season began, to make sure Horford -- or whoever wasn't starting -- wouldn't feel isolated or left out.

"It had a lot to do with Al," Tatum said. "I got so, so much respect for him, and knowing that he might be the guy coming off the bench and I didn't want it to just be a thing where we got new guys in, and it's like, 'All right, Al you're coming off the bench.'

"I know how much he's meant to this organization, how much he's meant to me. And just to have that talk ... basically we got six starters, and one of us has to come off the bench on any given night. I give Al a lot of credit."

Horford, 37, has but one remaining NBA goal, he said: to win a championship, and it's checking that final box on his NBA to-do list that is driving him.

"I think it's important for us to all have the same understanding and know that we're all trying to make sacrifices to be the best that we can," Horford said. "For some people, it's going to be scoring. For some people, it's going to be minutes, just different things like that.

As a team in general, [it's] us understanding that it's going to take different things to get us where we need to be."

FEW PEOPLE KNOW Tatum as intimately as Horford does. The two of them sit together on flights. Tatum has often cited Horford's influence on him as a young player, watching the way the veteran center went about his daily routines.

As Horford sat inside the visiting locker room inside Philadelphia's Wells Fargo Center, the site of so many battles between these two franchises over the past few years, the veteran center couldn't help but smile as he talked about how Tatum has matured off the court -- including taking the initiative to set up this meeting in the first place.

"He's taken a lot of accountability," Horford said. "I feel like it's been a progression with him, and it's been good to see him just continue to take steps as a leader, time after time. He doesn't have to be the guy that's going to be out there talking the whole time, but his presence is felt. I feel like he is leading us more as a group.

"I feel like now he's starting to see the bigger picture."

Beginning with calling his teammates together before what the franchise hopes is a championship-winning season. It's a role that fits the moment for Tatum and the Celtics. Marcus Smart -- long identified as the emotional leader of the franchise -- was sent to the Memphis Grizzlies in June as part of the three-way trade that brought Porzingis to Boston.

While the goal of that move was to give Boston more offensive versatility in the playoffs, it also cleared a path for Tatum to step into a bigger leadership role within the franchise.

"This was a time where, if you're not OK with it, let's talk about it," Tatum said. "I didn't want everybody to, before the season started, say, 'Yeah, I'm, I'm fine with it. Whatever.' And then, you know, we'll lose a couple games, and then things build up.

"It offered a time for us to all be on the same page and express that we were OK. ... It was a great meeting."

Those sentiments were echoed by his coach -- in part because he wasn't part of it. Mazzulla said that while there had been a "free-flowing" conversation about the meeting, and whether he should be part of it, he ultimately told Tatum that he was glad to just have the players get together and talk things through.

"To me, you can't have a great team or a great organization if you don't have guys like Jayson, Jaylen and Al that set the tone like that," Mazzulla told ESPN. "At the end of the day, our team's only going to be as good as they want it to be, and them allowing me to help push them when they need it. But the meeting was their idea and it was important that the six of them talk together because they all need to know how important they are to each other.

"Having hard conversations is hard in the world today. So for six people to be able to get together and talk, I think is super important. That's the environment that we're trying to foster where they feel that they can have those conversations. It's super healthy, and credit to them for doing it."

The Celtics have gone through plenty since the team drafted Tatum in 2017. Over the past six seasons, no team has played more playoff games (94) than Boston, and the Celtics are tied with the Warriors -- who have won two championships in that span -- for the most wins (52). Including Brown's rookie season in 2016-17, Boston's 112 playoff games is the most by any franchise that has failed to win a title during that span.

That is why this team went out and acquired Porzingis in June, and then traded for Holiday a few days after Milwaukee had sent him to Portland for Damian Lillard in September. With a roster this versatile and deep, there's only one result that will be acceptable in Boston this season.

And the Celtics are well aware that hard conversations alone won't be what lift Boston to that elusive 18th championship this season. But they set a foundation, one they'll be able to lean on in moments celebratory -- and not.

"I think if we want to be the team that we envision ourselves to be, I think that was a key moment for us," Porzingis said, "just to start off the season with the right mindset and right responsibility to each other."