How do the Boston Celtics build around an imperfect star?

When you’re 5’9”, the ceiling is layered thick with limitations. Get through the first barrier and there’s a similar one just like it, but stronger. But even when you reach the heights that nobody else thought you would, sometimes you’re still looking up at clouds.

The imperfect star is nothing new to the NBA. What is new is that today’s imperfect star is one of the smallest players in the league whom no one can seem to classify just right. On one hand, there’s the obvious—Isaiah Thomas is one of the best and most efficient scorers in the league. He gets to the hole, he can shoot from the perimeter, he can create for himself, he can create for others, and he gets to the line at an impressive rate. He led a team full of misfits and castaways to the playoffs two consecutive years by himself, doing enough to convince both Al Horford and then Gordon Hayward to join the team. He’s really good at what he does, and no one looks forward to defending him.

But on the other hand, players lick their chops at the opportunity to be guarded by him at all times. It’s not because he doesn’t compete or puts little effort on the defensive side of the floor, but he’s 5’9” with a wingspan not much longer than the guy you sit next to at the bar. Even if he plays picture-perfect defense, any good offensive player will still manage to get a clean shot off. The Celtics know that and try to help out on defense as much as they can, but that leads to weird mismatches, bad rotations, and worst of all, terrible rebounding.

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Last year the Celtics’ defensive rebounding percentage was 78.5% when Thomas was off the court, which would be equivalent to 6th in the league. When he was on the court, that number dipped to 73.6%, which is equivalent to dead last. Opposing teams’ offensive rebounding ratings went from being equivalent to 6th in the league when Thomas was on the court to 22nd in the league when he was off. That means that teams are getting multiple opportunities to score in each possession, and it’s no surprise that the Celtics were 4th in opponent second-chance points during the regular season. Those numbers get even worse in the playoffs, where the Celtics were the worst defensive rebounding team and gave up the second-most second-chance points. There are obviously other factors that could go into this discrepancy, but the negative defensive impact Thomas has is clearly not just limited to his individual man, but his presence systematically puts a limit on how well the Celtics can defend. Yet at the same time, his offensive production, (specifically last season), still made him a net positive despite his shortcomings as a defender.

But how sustainable is this stellar performance? It’s fair to think that if Thomas takes a step back in production, his defensive limitations won’t justify keeping him on the court. That line of thinking is exaggerated even more when you consider the new addition of Gordon Hayward, a rising star in the league who has shown the ability to be the number-one option on a team without the warts of bad defensive play. If Thomas can’t have another year similar to last year, the Celtics may be in a weird position where they are at their best without the player who has been the heart and soul of the team for the past three seasons. This might even lead to more questions on why the Celtics passed up on Markelle Fultz in this year's draft.

But let’s slow down just for one second.

Thomas may never be a net positive defensively, and he may always put a strain on his teammates on that end, but to say that his value is based on an unsustainably elite offensive production is to pretend that he was surrounded by the perfect team—and last year’s team was from it. For example, let’s start with Avery Bradley. An NBA Twitter sensation, Bradley has always been at his best when he gets to guard opposing point guards. But Thomas is too undersized to defend any other position, and Bradley is not usually able to create for himself. The two ended up being a nice pairing offensively, but they were not a great fit on defense, where Bradley’s strengths ended up being neutralized. Additionally, as Bradley is undersized himself, having both him and Thomas on the floor led to even more rebounding problems. (For those of you who are about to furiously cite to me Bradley’s rebounding numbers, keep in mind that 88.5% of those rebounds were uncontested and that the team rebounded worse when he was on the floor.) To be fair, this isn’t exactly a fair criticism of Bradley—he’s a skill-specific player who has been given a role that was better suited for a different type of skill, but these issues do highlight the poor fits that surrounded Isaiah Thomas.

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Let’s also take a look at Amir Johnson. Though he is by all accounts a great teammate, the acquisition of Horford meant that Johnson had to go from defending and playing on the perimeter (where he was more comfortable) to using his thin 6’9” frame to battle with legitimate NBA bigs. The results were as expected—Johnson broke down as the year went on, and the Celtics faced a big problem. They were essentially playing a small-ball lineup with Johnson at the 5 but not getting the speed and versatility that are the main draws to such lineups. Johnson struggled to grab boards and protect the paint, and on offense he continues to be a predictable screener in the pick and roll that isn’t going to hurt you unless he rolls and, even if he does, getting to the basket and finishing was no guarantee. Similar to Bradley, this wasn’t necessarily Johnson’s fault. He’s best used as a reserve big in limited minutes. But it also highlighted that, along with pairing Thomas with another undersized guard who was playing out of position defensively, the main rim protector they had was an undersized player who was mostly overwhelmed by the size and the strength of his opponents, and was constantly dealing with a nagging ankle injury that may persist for the rest of his career.

Furthermore, there wasn’t much clarity on the bench, which was highlighted by the young and erratic (Marcus Smart), the young and inconsistent (Terry Rozier, Jaylen Brown, and Kelly Olynyk), the one-trick ponies (Gerald Green and Jonas Jerebko), and the guy that may be better served playing overseas (Tyler Zeller). The team not only had no real identity, but it was ill-suited to help Thomas cover for his defensive flaws, causing casual fans to question Thomas’s limits more than the foundation around him.

This summer may always be highlighted by the pre-draft trade and the signing of Gordon Hayward, but the biggest move the Celtics made this summer was choosing Isaiah Thomas. It’s easy to forget that the Celtics were planning on pursuing a rebuild strategy similar to the Sixers and nearly didn’t make the deal for Thomas because they worried about how it would affect their draft stock. And all it took was two seasons to turn Boston from a cute start-up to an NBA heavyweight primed to give LeBron James a run for his money. The front office brass realizes the impact that Thomas has made on the team and city, and rather than deal him away or give him the impression they’re looking for his replacement, they’ve done the complete opposite by finally giving him a team that can actually compliment his game.

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The Celtics made a concerted effort to increase their size on the perimeter and beef up their front-court presence. The additions of Gordon Hayward, Marcus Morris, Jayson Tatum, Aron Baynes, and Ante Zizic give the Celtics added length and strength that they haven’t had since the Big three era, and these moves simultaneously allow Stevens to continue to play small ball. Instead of starting the 6’0” Avery Bradley, the team can choose to start the 6’4” defensive menace Marcus Smart or the 6’7” Jaylen Brown. (With Jaylen Brown was in the starting lineup last year, the Celtics defensive rebounding rate jumped to 81% and the defensive rating was at 90.6 via NBA.com). Or, maybe they pair Baynes with Horford and slide Hayward to the off-guard spot. Regardless, the Celtics are going to have four other players surrounding Thomas who are big, versatile, and can compliment him on the offensive end. Armed with maybe two or three other players that can run the offense on one end, and four other guys who are big enough to handle their position and versatile enough to switch seamlessly, the Celtics will finally be providing Thomas with players that can help him score and will have his back defensively in a way that Boston has not seen before with Thomas in the lineup.

Will the Celtics still defend and rebound better when Thomas is off the floor? Probably. But if the Celtics can at least rebound at an average level with Thomas on the floor and cut down on second-chance opportunities, then the net value Thomas adds offensively would substantially outweigh any defensive dips rather than narrowly help him maintain positive net value.

Thomas is an imperfect star in a world where seven footers move like wings, one team has a near-monopoly on MVP candidates, and the best player in the world has had a stranglehold on the Eastern Conference for the past decade. But Thomas has proven time and time again that he’s capable of impacting winning in a tremendous way when given the opportunity. Every year he’s gotten better and taken the team with him as well. He’ll never singularly have the impact of stars such as Kevin Durant, LeBron James, and Kawhi Leonard, but guess what? No one else in the league has players that do. For the rest of us, you take the best of what you have, and you do everything you can to enhance its value. Boston has finally made its choice.