Take a trip down the rabbit hole of Danny Ainge’s transaction page on Basketball-Reference once more for old time’s sake. Explore that page long enough, and it will reveal a nonlinear method of rebuilding from scratch filled with endless possibilities. Remember that Keith Bogans’ shell contract begat Abdel Nader and that Tayshaun Prince was briefly a Celtic. Recall the one that haunted Sam Hinkie; Jordan Crawford for Philly’s heavily protected first pick that became a pair of inconsequential seconds. Pour one out for the time Ainge used a cap exception to secure a late first-rounder that got Isaiah Thomas. Raise one final toast to the time he picked up Jae Crowder in the Rajon Rondo deal. You should also take a moment to remember all the deals that never happened: a bushelful of picks to move up in the draft to take Justise Winslow, trades for Paul George and Jimmy Butler that broke down on various draft nights, and not getting Kevin Durant in free agency. “It never goes the way everybody wants it to go, you know?” Ainge said with a slight chuckle during training camp. Take one last look around because those days are suddenly over. What had been an endless series of moves spiraling into nebulous directions has suddenly come into clear focus. The end result is a core featuring Kyrie Irving, Gordon Hayward, and Al Horford with as many as five rookies and nine other new additions to integrate into the lineup. Even in the hyperdrive reality of the modern NBA when roster turnover is inevitable, the Celtics offseason was extreme. Not that it was completely unexpected. “I loved our team last year,” Ainge says. “I had a blast. I really enjoyed it. I knew we weren’t a championship team with the Warriors and the Cavs, but I thought the team achieved all they could.” Ainge pushed back at the suggestion that last year’s group had run its course, but nevertheless he went into the offseason looking to acquire veteran star power. He made a run at George on draft night, then turned his attention to Hayward in free agency. That, in turn, necessitated trading Avery Bradley for Marcus Morris to balance the cap ledger. And that was supposed to be that. Until Kyrie Irving became available. The blockbuster deal for Irving involving Thomas, Crowder, and the last of the vaunted Brooklyn picks was announced in late August, traditionally the quietest part of the NBA calendar. It was stunning in that teams that compete in the conference finals simply don’t trade key players to one another. It was also stunning in that Ainge had finally traded away his most prized asset to forge a completely new team. Some of it was opportunity; players like Irving don’t usually become available. Some of it was timing with key contracts coming due. And some of it was uncertainty over Thomas, who is hoping for a late December return with the Cavs from a hip injury. All of it just kind of happened. The Celtics believe that they are better-positioned for the future with a clearer cap situation. They think they’ll be better in the postseason with two elite playmakers along with Horford, and they think their young players are ready to step into larger roles. In other words, this is really who they are for the foreseeable future. “There will always be changes and we’ll have to tweak it but yeah, we have no intention of blowing our team up again next summer,” Ainge said. “That’s for sure.” But who are they? Nobody really knows. Of all the contenders that made wholesale changes in the offseason, none is as opaque as the Celtics. To begin to understand them, we need to start with the question of identity.

If you compare Irving’s career numbers with Thomas’ from the impartial distance of a spreadsheet, they look remarkably similar. Both are scoring point guards who utilize a high number of possessions and both have issues on the defensive end. They are both certified All-Stars and elite scorers. Beyond the data, though, you’d be hard-pressed to find two more different players. Irving has always been basketball royalty, a top recruit at Duke who went first in the 2012 draft. He is sleek and skilled, a ball-handling virtuoso and brilliant shooter who slips between cracks and unspools textbook perfect jumpers. He plays with the easy confidence of a can’t-miss prospect who once made the biggest shot of an NBA season. For all of his gifts on the court, Kyrie has been a cypher off the court for most of his career. He shocked many with his trade request (who would want to leave LeBron James?) and seems perpetually unbothered by the prospect of leading a franchise in pursuit of a championship. Beyond his dabbling with the flat-earth society as a means of challenging social constructs, there is little that we know about Kyrie Irving. Thomas, on the other hand, plays with the vengeful hellfire of a man scorned. The last pick in the same draft class the year Kyrie went No. 1, the All-Star that coaches wanted to bring off the bench, the little guy who challenges the giants by going right through them, Thomas exists to prove others wrong. You never have to guess what he’s thinking because he’ll tell you right to your face. He personified the character of the 2016-17 team perfectly. Like Thomas, many of the players had been overlooked and undersized. They played with a snarl and a chip on their shoulders that even their detractors — and there were many — could appreciate their effort. “Last year our identity was a feisty group of kids that played really hard. But we did rely on Isaiah a ton.” Pull back from the raw emotion that team engendered to the safer distance of the salary cap sheet, and the trade makes logical sense. Kyrie is younger and under contract for one more season beyond this one, when he has a player option. If you commit to him, you are securing the prime years of his career. And yet, by trading Thomas and Crowder, as well as Bradley, you are also exchanging your hard-earned persona for a blank slate. “Last year our identity was a feisty group of kids that played really hard,” Ainge says. “But we did rely on Isaiah a ton.” That but is the biggest reason for all the change. When Thomas was out of the lineup, the Celtics struggled to score. While Thomas performed magnificently in the postseason, those team-wide offensive shortcomings were magnified, especially by the Cavaliers, who blew them out in five games while Thomas was sidelined by his hip injury. That weakness was first addressed by signing Hayward, a seven-year pro coming off his best season right in the prime of his career. He gives the Celtics offense flexibility the team hasn’t enjoyed since Paul Pierce was still roaming the Garden floor. Together with Horford, who is a skilled playmaking big man, the Celtics now have multiple options where before they were limited. There was still the dicey matter of Thomas’ hip, and that’s where it gets complicated. Could they have gone into this season without one of their most important offensive players for at least the first few months? That question stopped being rhetorical the moment Irving became available. Irving’s arguably the best one-on-one player in the game and has proved capable of taking over playoff games all by himself. Ainge refers to him as a “born basketball player,” and adds that, “Kyrie has proven that on the biggest stages against the best players in the world he’s one of the elite players.” To make the deal, Ainge had to not only part with two of his core players, he also had to throw in the highly valued and much-discussed Brooklyn pick. Ainge caused a few ripples among the hardcore faithful when he suggested that he had a responsibility to Horford and Hayward to put the Brooklyn pick on the table in trade talks for Irving. “Here we are asking those guys to come in with an opportunity to win and they did,” Ainge says. “They chose us over other teams because they believed that we’d do what it took to win. So it’s hard to recruit free agents and not do all you can to win. I did feel like there was some responsibility to those guys.” Viewed from that perspective, Ainge’s methods come into an even sharper focus. Horford doesn’t sign without a stable environment already in place. Hayward might still be in Utah if he didn’t think the Celtics were a viable contender. And Irving may not have been so anxious to join a team without those two already on the roster. As much as cap space and tradeable assets, this is how contenders are built and maintained in the modern NBA. Loyalty at the top of the NBA food chain is as much between players as it is between teams, and Ainge has tried to turn the Celtics into a destination for stars to consider. What he’s looking for now is continuity, which sets up an interesting experiment this season. How do you get a team with 11 new players to perform as one?

The Celtics don’t have a captain, which isn’t that surprising. They haven’t had one since Rajon Rondo was traded. If there is a central figure in the locker room, it’s probably Horford. He’s not a forceful personality the way Kevin Garnett was a culture change unto himself. Horford, rather, is a stabilizer. “I want to help our guys in any way I can to make them better,” Horford says. “Just be a good example for them and making sure I’m challenge them on the court and we’re growing as a group. Everybody wants to label one guy as a leader, but I feel like we have many leaders on this team. That’s the way to do it. When you have a locker room with only one leader, you should worry.” Horford pointed to Irving’s championship experience and Hayward’s professional example. He cited Marcus Smart’s vocal contributions. He noted Jaylen Brown’s precocious development and veteran big man Aron Baynes, who provides toughness and savvy.

That’s a good start, but chemistry is not easily sourced, nor is it easily gained. It’s one thing to assemble the pieces of the puzzle, and it’s quite another to execute on the court. Through the course of their one season together, Horford and Thomas were able to develop a dynamic that fueled their offensive possessions. Now he needs to do it again with Irving and Hayward. The frantic pace of player movement has accelerated this team’s learning curve, and all three understand that it largely falls on them to rewire the team’s approach. No one is under the impression that it will take place overnight, least of all Brad Stevens who is tasked with organizing a structure around which all the new pieces can become whole. “It’s like a brand new job,” he says. Stevens has simplified some of his concepts and impressed upon his coaching staff the need to remain flexible and malleable to adjustments when needed. He’s been impressed by how quickly his team has picked up its defense, which requires trust and communication. For Stevens, this is not about X’s and O’s. It’s about creating a framework for his team to find itself. “All that stuff happens when you’re focused on winning,” he says. “All the other stuff about spending time together, we’re eating meals together, and we’re going to be around each other for a long time. That’s not just what it’s about. Do I know what the guy next to me does well, and can I put him in position to do that? Everyone’s intent is already good.”

What is it that makes Brad Stevens so darn good? His after-timeout plays are so nifty that my colleague Tom Ziller has dubbed him the Michael Jordan of the Whiteboard. His offenses are heavy on player motion and rely on crisp, unselfish passes out of their actions. His defenses cover up weaknesses and utilize strengths. When you look at a Brad Stevens team, you see a well-coached team. All that is true, but it still doesn’t get into the heart of the matter. “Brad’s one of the greatest coaches because he allows you to go out there and play and be you,” Marcus Smart says. “He doesn’t try to make you anything else but you, and he allows that. He puts you in the right places to have success.” Few players need to be themselves more than Smart, who is blessed with a competitive streak that mandates playing time. He will guard anyone. He will go after loose balls and tough rebounds and play with an edge to the point of recklessness. There will always be a place for someone like that, but he has been defined in the minds of many by his weaknesses. Smart’s primary issue is his shot. He’s a 29 percent three-point shooter for his career and unless that improves, teams will continue to exploit that hole in his game. When he was struggling last March, Stevens told Smart that he had confidence he would make them when the game was on the line. Smart hit 39 percent of his threes during the postseason. “The bottom line is he needs to know that we think that too,” Stevens says. “I believe in Marcus. He’s a winning basketball player.” His other weakness was his weight. Smart was carrying around 240 pounds during the playoffs, and his conditioning was becoming an issue. In the offseason he shed 20 pounds thanks primarily to an overhauled diet...and thus was born Skinny Marcus. “It’s what you eat,” Smart told me while munching a post-practice banana. “It defeats the purpose to go be in the gym for two, three hours and go home and eat a burger.” Skinny Marcus has been the talk of training camp, draining threes in the first preseason game and becoming a vocal leader for a defense that relies on switching as much as any team in the league. He wants to become a more complete offensive player, getting into the paint to create for his teammates and earning trips to the free-throw line. Stevens approves, of course, but he’s not taking any credit for it either. “You can lead people in certain directions as much as you want, but ultimately it’s got to be their decision,” Stevens says. “That’s why I respect Marcus so much. He made that call.”