For the past few seasons the Celtics have been scrappy, smart, lucky, tough, overrated, injured, resilient and almost always very good. Now Kyrie Irving and his teammates will try to take to next the step.

This story appears in the October 22, 2018, issue of Sports Illustrated. For more great storytelling and in-depth analysis, subscribe to the magazine—and get up to 94% off the cover price. Click here for more.

Among outsiders, Kyrie Irving can be difficult to read, and mentioning this to people in Boston will generate a variety of reactions. Danny Ainge laughed: “I get a kick out of Kyrie. I read things he says, I think he intentionally makes himself a little bit challenging to read. I think he enjoys that.” Terry Rozier confirmed the premise: “He can be a totally different person than what the cameras show and what y’all see.” Brad Stevens spoke in cliches: “Obviously he’s a tremendously talented guy on the court, but I appreciate how he thinks. I appreciate his creativity. The way he goes about things on and off the floor.” It was only Al Horford who was willing to tell the full truth here: “I mean, I think he’s hard to read among insiders! You know, he’s a different guy.”

The Celtics should be the second-best team in basketball this season, and since roughly half of sports media somehow has ties to Boston, you’ve probably heard about this. They have an endless supply of versatile wings, they have Horford anchoring everything on both ends, they have Stevens to deploy all these weapons and get the best out of everyone. Then there is Kyrie, the player who gives them a chance to be great.

Here’s what we know: While half the NBA spent the summer working out in L.A. and broadcasting it on Instagram, Kyrie spent several weeks in Seattle with Jamal Crawford and never posted a thing. He met Bill Russell while he was up there. He picked out his mini-Afro to give himself a more 1970s look for the occasion.

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He is no longer working off a strictly plant-based diet, because it turns out that professional athletes need protein, but he still admires the vegan lifestyle. He was recently the keynote interview at the Forbes Under 30 Summit, where he apologized for publicly wondering whether the earth was flat. (“I’m sorry about all that,” he said, “for all the science teachers coming up to me, like, ‘You know I gotta reteach my whole curriculum?’ I’m sorry! I apologize.”)

When he arrived in Boston for media day, Irving said that he’s happy, settled and peaceful—unlike last season, which began with league-wide debate over why he forced a trade from the Cavs. “O.K., what if I add a little happiness to playing basketball?” he told reporters of this year’s approach. “Maybe we’ll see what that looks like.” He also admitted that last season was more stressful than he ever let on. “It was just so fast,” he says. “Going from one professional environment to another. . . . I’m human at the end of the day, trying to play the game with all the distractions outside the court. It was just like going through a bad breakup. I tried to deflect as much as possible while showing the love I have for Cleveland. But it was time to move on. It’s human nature. Sometimes it’s time to pick up your stuff and move on. I wanted to do it happy, but I couldn’t.”

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As the year progressed, there was lingering knee soreness and season-ending surgery in March. He watched from home as LeBron James and Cleveland beat the Celtics in Game 7 of the East finals. “The expectations,” Irving says. “You’re trying to live up to that, and then you lose focus and lose sight of yourself. You start worrying about what everyone else is doing. It takes a toll on you.” He is not interested in talking about LeBron now—though a close read of Kyrie in Boston might make you reconsider what he learned in Cleveland.

After a summer of whispers about what he might do next July, Irving came back to Boston and gave interview after interview in which free agency was addressed. Each one came with strong hints that he plans to stay where he is. He was not interested in spending the year surrounded by free-agency headlines. Finally, in early October, at an appearance for season-ticket holders, he flat-out told Celtics fans he plans to commit long-term next summer. “If you guys will have me back,” he said, “I plan on re-signing here.”

When he first asked out of Cleveland, conventional wisdom held that Kyrie wanted “his own team,” and that’s what he found in Boston. That might not be quite right. “I wouldn’t say he thinks it’s his team,” Ainge says. “He heard enough of that in his career that, I think, that doesn’t sit well. He wants to be part of the team. But he’s our best player.”

When asked to pose on the cover of Sports Illustrated alongside Gordon Hayward and Horford, Kyrie declined. “Big three, big four. . . ,” he says. “With this team, it just can’t happen. We all play a huge role in making this a championship-caliber team. I’m grateful for the opportunity, but if it’s not all of us, it’s none of us.”

In general, Irving isn’t very interested in talking about his own accomplishments. He is ambivalent about his playoff heroics in 2016 and recently explained that he wasn't as emotionally invested in that Finals run as he should have been. He’d much rather talk about his responsibility to teammates like Jayson Tatum, Rozier and Jaylen Brown, all of whom are 24 or younger. “It’s helping out the younger generation,” Irving says. “They are the future of our league. Obviously, I’m presently here. But those guys are really, really special. I’m not the veteran that’s mad that everyone is taking more shots. Nah, man. I want to see a great team.”

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The story of Boston’s season will be the starting five—Irving, Brown, Tatum, Hayward, Horford. With that group, the Celtics are a series of matchup nightmares that can buzz through teams on both ends of the floor. At Golden State’s media day, Klay Thompson was asked about challengers. “I like the team out East,” he told ESPN. “In Boston. One through five—they’ve got a team that kind of mirrors ours, as far as their length, guys who can shoot and play defense, and an unselfish way about things. They are going to be a team to reckon with.”

It wasn’t a particularly bold stance. Anyone who’s paid attention to basketball conversations for the past five months understands how highly regarded this Boston team is. Celtics players sense the possibilities too. Horford said that last season was the most fun he’s had since college but that this is the most talented team he’s been on. Reserve forward Marcus Morris said that if opposing bench units aren’t ready, it will get real ugly. Guard Marcus Smart said that runs between the first and second units have been a bloodbath.

Every team feels good and says the right things in training camp, but there’s a particular kind of buy-in that seems different in Boston. “We’re all anxious,” Rozier says. “We’re ready to get after it.”

The question is how long it will take to come together. Even with no major additions this summer, this is a different team than last year. What roles will everyone play? How will the bench will adjust? Will everyone be satisfied? Winning ultimately solves most problems, but if there is some angst along the way, it would make sense. Half these players are just beginning to establish themselves on the NBA landscape, and everyone is competitive. To Ainge, it brings to mind his days as a Boston point guard: “There were times when I thought I was better than Larry Bird and someone had to talk me off the ledge.”

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Hayward, who last year was lost for the season five minutes into his first regular-season game as a Celtic, will likely score less in Boston than he did in Utah. And while his abilities as a playmaker and shooter figure to make him a steadying presence with any lineup Stevens deploys, it may take a few weeks (or months) before he finds a rhythm and identity within Boston’s scheme. Meanwhile, Jaylen Brown has worked diligently to improve his ballhandling, but with four scorers alongside him, there will be games when Boston is better off with him playing like a 3-and-D wing instead of alternating huge scoring nights the way he and Jayson Tatum did last spring.

“The way they embraced it,” Horford says of Brown and Tatum in last year’s playoffs, “it’s going to set them up for the rest of their careers.” That will probably be impossible to dispute a few years from now, but this season may be a more complicated story. Brown will have to pick his spots in a role that could be more limited than he’d like. Tatum was so good as a rookie that it will be difficult to improve certain areas of his game—43.4% from three-point range—while mastering others may take longer than one offseason. Despite the arrival of rookie Robert Williams, Tatum is still the youngest on the team (“Look up Rob’s birthday,” he yelled to an assistant before Boston’s first preseason game.) He’s got the highest ceiling of any young wing in the league, but learning when and how to take over games is tricky for any young player. It becomes even trickier when you’re spending every game surrounded by stars.

Stevens spent the first few days of training camp reminding anyone who would listen that, coming off a big year, it would be human nature to forget why last season was successful. After a preseason loss to the Cavs, he said, “I couldn’t be more unimpressed after our first three exhibition games.” Asked whether the team was making an adjustment that would take time, he said, “I don’t think it should be an excuse for [not] doing things right.” Asked for points of emphasis going forward, he mentioned the defense: “Wide-open layups, wide-open threes, wide-open shots, fouls . . . pretty much everything.”

Ainge, for his part, has been quick to qualify some of the hype surrounding this season, noting that last year’s Celtics were lucky to avoid the Wizards and the Raptors in the Eastern Conference playoffs. As for any Golden State questions this season, Ainge says, “We’re not a good enough team to be obsessed with one team.”

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Now thatobligatory disclaimers have been made, concerns have been noted, and patience has been preached, it’s important to add that this team should get the benefit of the doubt until further notice. Stevens has overachieved in each of the last four seasons, and Boston will have a wider margin for error than any team in the East. The bench will feature five players—Smart, Rozier, Aron Baynes, Semi Ojeleye and Morris—who started a playoff game last season. The starters may make Warriors comparisons unavoidable. For the past few seasons the Celtics have been scrappy, smart, lucky, tough, overrated, injured, resilient and almost always very good. This year is different.

The best runs throughout NBA history are the by-products of skill and luck. In Golden State, that meant drafting Steph Curry and stumbling into Draymond Green in the second round, then having the foresight and ambition to exploit every advantage those players created. In Boston, the Celtics won’t have four Hall of Famers in their lineup, but they’ll be reaping the benefits of that same interplay between serendipity and foresight.

Three top 10 Nets picks—the by-product of a historically lopsided 2013 trade that sent creaky versions of Paul Pierce and Kevin Garnett to Brooklyn—allowed Ainge and an elite front office (Mike Zarren, Austin Ainge, Dave Lewin) to spend the past three years carefully building for the future with the assets of a tanking team while stocking the back end of the roster with shrewd bargains. Those Nets picks became Brown (No. 3 in the 2016 draft) and Tatum (No. 3 in ’17), while last June’s Nets pick (No. 8, which was used by Cleveland on Collin Sexton) was the centerpiece of the deal that brought Kyrie to Boston. On the court, Stevens helped the team exceed expectations in each of those seasons, and the success transformed Boston into an attractive destination for free agents like Hayward and Horford. Now it's all coming together on one team.

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Hayward’s ultimate role in Boston is a still a work in progress. Horford’s is not. Ask Stevens about everything his big man has done for this team since he signed in 2016 and the coach says, “I can’t even. . . . I don’t even know where to start. I’m just amazed by his presence, and what he does every day to play to his strengths on both ends of the floor. But really, he just gives off a tremendous amount of belief to others. He’s an elite leader. That’s two-fold: it’s the way he plays, and his personality.”

For every story that tries to explain the success of the Celtics this season, there will be an alternate version that is less-exciting but probably more accurate: Horford is the most important player on the team. The things he does well are subtle and not particularly thrilling if you’re not a basketball coach—successfully rotating on defense, finding every cutter on offense—but he's the cornerstone for the team’s identity on both ends of the floor.

He makes everyone life's easier on offense, and in last year’s second-round series vs. the Sixers, Horford alternated between guarding Ben Simmons and Joel Embiid, and he got the better of both. He’s ridiculous. Says Ainge, “He can play big, he can play small, he can play fast, he can play slow. On the outside, On the inside. Guard multiple people. He’s like the perfect guy, he can play any style of basketball.”

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There is a paradox to the Horford conversation, though. Once you appreciate everything Horford has done in Boston, it’s hard not to wonder how much longer he can continue doing it. He is 32 years old. His friend and teammate at Florida, Joakim Noah, has been a well-paid bystander for several seasons now. In general, looking around the league, there aren’t many examples of big men past the age of 30 and still playing at an All-Star level.

Preseason concerns about minutes and chemistry will likely look overblown in a few months, but if anyone is looking to seriously second-guess Celtics hype this year, the player who holds them together is the area worth monitoring. Horford understands this concern, but he says he is taking the long view to keep himself fresh. Stevens will monitor his minutes closely, and Baynes will platoon with a now-healthy Daniel Theis in relief.

As for the future, Horford can also opt out of his contract to become a free agent next summer, but at the moment, he sounds as committed as his point guard. “If they want me here, I’m very happy,” Horford says. Looking around the brand-new Celtics practice facility at his teammates, Horford points out that it wasn’t like this when he first decided to come to Boston. He remembered the recruiting pitch, sitting in front of Stevens, Ainge and owner Wyc Grousbeck. They told him about “all these assets.” There were picks, there was cap space. “Maybe we sign a superstar here or there,” they told him. “We’re able to make a trade. We’re able to really make a team that’s great.”

Explaining Kyrie Irving in the playoffs is nearly as difficult as understanding him off the court. In three Finals appearances, Warriors writers have noted that controlled the pace and took that Golden State team out of its rhythm. A Celtics staffer explained that Irving specializes at beating the switches that are ubiquitous at the highest levels of basketball. Ainge says it's simpler than that: “He's a good player! He's just a really good player. And really good players look for those opportunities and thrive.” While Horford says that Irving makes any gameplan complicated: “You don’t know quite how to cover him. Like when you scout a player, you have a general idea of what they’re going to do. And he does a lot of things that people prepare for, but he also does other things, at pivotal times, where you’re like, ‘I wasn’t predicting he was going to do that.’ ”

Boston has enough talent to win 55 or 60 games regardless of who plays point guard, but however you choose to explain it, Kyrie is irreplaceable when it’s time to challenge the best teams in the league. He is one of the best finishers at the rim the NBA has ever seen in a point guard, he’s got the best handle on the planet, and he can create space at will to get clean looks in crunch time. Those skills are what the Celtics were missing last May—Boston scored one point in four minutes as the Cavs took control in the fourth quarter of Game 7—and they are probably what the Celtics will need if they make it to June this season. Horford anchors the foundation; Irving raises the ceiling.

It’s strange, though. His defense comes and goes. His passing does the same. There are nights in the regular season where he looks like a glorified chucker posing as a franchise player. His health has been sketchy. He used to think the earth was flat. There are some real question marks here. But then he will have a moment at the end of a game where he leaves the defense frozen, gets whatever he wants, makes it look easy and makes you wonder why anyone has ever cared who plays defense during a regular-season game in January.

All of this is what makes him fascinating. It’s not about LeBron, or conspiracy podcasts, or helping young teammates, or emotional investment in iconic Finals moments. Kyrie says lots of things. Not all the talking points are as interesting as they seem.

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On the court, there is no puzzle quite like him. During the 2016 playoffs, I found myself in a heated argument with an NBA player who swore up and down that Kyrie was the most skilled offensive player in the league. Steph Curry had just finished having one of the greatest offensive seasons the NBA had ever seen. It didn’t matter. One-on-one one, the player said, Kyrie is more talented than anyone in the league. It sounded crazy at the time—midway through the 2016 Conference Finals—and maybe it was. But then two weeks later, Irving spent the second half of the Finals outplaying Curry on the way to a title.

That conversation in 2016 is typical of a phenomenon that has colored Kyrie’s career all along, and it continues now that he’s in Boston. Ask any basketball blogger to explain the Celtics as championship contenders, and they will probably point to Horford. Ask fans or coaches, and they may point to Stevens. Ask opposing front offices, and they will grumble about the Nets trade. But ask actual NBA players, and almost all of them will mention Kyrie first. Players have a reverence for his game that’s hard to explain but impossible to dispute. Just last week one NBA star told SI, “Nobody that’s ever played that position can do what he does. He plays like Kobe. He can score on bigger players. And he plays better when the stakes are higher.”

Whether you agree with that assessment or not, the next few seasons will give Kyrie a chance to live up to the billing. Several years of careful building have given Boston one of the best foundations in the league, and this year his presence as a closer is what gives the Celtics a chance to do something crazy. Or, more accurately, his presence is the one factor that might make you pause before dismissing the possibility.

Kyrie understands all of this. And so, after several minutes discussing his newfound peace and leadership responsibilities in Boston, he smirked when asked about his value in the Finals. “I can go get a bucket,” Irving said. “And the Warriors know it too. Going against them for three straight years, you develop that sort of competitive rivalry. But the respect is there. Obviously, they’ve been the victor two out of three times. You give respect where it’s due. They’re a special unit. But sometimes special units can be beat by special individuals.”