Real or not: The defense behind the NBA’s five most surprising starts

As the NBA season nears December, there are a number of surprise stories at the top of the standings, highlighted by the draw for the knockout phase of the inaugural in-season tournament.

In the East, the Orlando Magic would have home-court advantage in the playoffs if the season ended today, while the Indiana Pacers — the first team to book a spot in the in-season tournament quarterfinals — would be the No. 6 seed in the East, after both missed the postseason last year.

Out West, the Minnesota Timberwolves and Oklahoma City Thunder are the conference’s top two teams after both were in the play-in a year ago. And the Houston Rockets have surged from the league’s second-worst record to above .500, good enough to make the play-in if the season ended today.

For most of these teams, defense has been a winning formula. Houston, Minnesota and Orlando boast three of the NBA’s top four defensive ratings, while Oklahoma City is not far behind at No. 7. By contrast, the Pacers are one of the league’s worst defenses on a per-possession basis but have managed to outscore opponents with the most efficient offense in NBA history to date.

Which of these surprise stories is likely to continue beyond the conclusion of the in-season tournament? And which Cinderellas might see their coach turn back into a pumpkin? Let’s break down their chances using advanced stats.

Houston Rockets

Of the three surprise teams at the top of the defensive leaderboard, the Rockets look most at risk of regression going forward — with an interesting caveat. The New Orleans Pelicans are the only team with opponents shooting a worse 3-point percentage against them than Houston (32%), which typically doesn’t tell us much about how well opponents will shoot going forward.

The exception to this rule has been new Rockets coach Ime Udoka’s former team, the Boston Celtics. Boston has ranked in the NBA’s top 10 in opponent 3-point shooting 15 of the past 16 seasons, including the league’s lowest percentage during Udoka’s lone season as head coach (2021-22). There has been carryover with other coaches involved in that streak. Doc Rivers’ teams have been in the top 10 in opponent 3-point percentage in nine of the 10 seasons since he left Boston, while Rivers’ former assistant, Tom Thibodeau, had teams in the top 10 in seven of his 10 full seasons.

Better yet, Houston is forcing the right kind of shots. Based on Second Spectrum’s quantified shot quality metric (qSQ), which considers the distance and type of shots and location of nearby defenders, only the Detroit Pistons would be expected to allow a lower effective field-goal percentage (eFG%) than the Rockets thus far. That Detroit is 14th in this category shows the importance of shot-making and rim protection, but Houston’s process has been good.

Based on opponents’ shot quality, one of the four defensive factors, and the other more stable categories (defensive rebounding, turnover rate and free throw rate), we’d expect the Rockets to be around the NBA’s 10th-ranked defense going forward. That suggests some drop-off from their current perch, albeit still a dramatic improvement over last year’s 29th-ranked defense. Given the upgrades to Houston’s offense with the addition of Fred VanVleet and Alperen Sengun’s development, which I covered in a recent mailbag, the Rockets look capable of staying in the play-in race all season.

Indiana Pacers

Among the teams that finished undefeated in the in-season tournament group stage, none had better timing than the Pacers. Indiana has gone 3-6 in its nine November games that haven’t counted toward the in-season tournament but was a perfect 4-0 in group play. The Pacers lost to the Philadelphia 76ers in a Sunday game that wasn’t part of the tournament and then beat the Sixers in Philly two days later to ultimately decide first place in East Group A.

After Monday’s home loss to the Portland Trail Blazers, the Pacers are no longer overperforming preseason expectations of a play-in run quite so dramatically. Still, their above-.500 record and solid point differential (plus-2.8, 12th in the league) are better than anticipated thanks in large part to the play of Tyrese Haliburton.

Haliburton might not be able to maintain his current 50/40/90 shooting splits, which have been bolstered by a career-best 46% beyond the arc, but those numbers aren’t far from his previous performance. Haliburton’s usage rate has grown to 26.5% from last year’s high-water mark of 24%, amplifying the impact of his efficient scoring.

Perhaps the biggest question for whether Indiana can maintain a 122.5 offensive rating that would surpass last season’s Sacramento Kings (118.6) for the highest in NBA history is health. Of the team’s top six players in minutes per game, Haliburton is the only one to miss a game — a 51-point loss at Boston. The Pacers’ offensive rating drops by 15 points per 100 possessions with Haliburton on the bench, according to NBA Advanced Stats, so any absence would bring Indiana’s offense back to the pack and expose the team’s dreadful defense.

Minnesota Timberwolves

To some degree, Minnesota’s start is less surprising. The Timberwolves were the only team in this group to reach the playoffs last season, when they were competitive against the eventual champion Denver Nuggets in a five-game series. My preseason projections had Minnesota with the best expected record in the West, though only after Steven Adams’ injury bumped the Memphis Grizzlies down to No. 3.

At 13-4, the Timberwolves are still comfortably ahead of that projected pace, and only the Magic are performing better relative to their preseason over/under wins total of 45.5 games. After seeing opponents shoot just 31% on 3s during the season’s first nine games, Minnesota has been near league average since.

Based on average or better performance in each of the four factors besides opponent shooting (where they’re No. 1), the Timberwolves are forecast as the league’s fourth-best defense based on the quality of shots they’re allowing so far. They can afford that slippage and still remain among the league’s top teams.

Health is, again, the biggest obstacle to Minnesota maintaining its pace. Of the team’s top nine players in minutes per game, eight have played every game, with starting small forward Jaden McDaniels the lone exception. Not coincidentally, two of the Timberwolves’ four losses have come in the six games McDaniels has missed. If Minnesota remains reasonably healthy, this looks like a top-four team in the West.

Oklahoma City Thunder

For Oklahoma City, the leap near the top of the West standings is ahead of schedule. There’s no doubting the Thunder’s talent, but no team this young (their average age, weighted by minutes played, is 23.7, second lowest in the NBA behind the 2-15 Pistons) has been this good since, well, Oklahoma City a generation ago.

Back then, in 2009-10, the Thunder’s average age was 23.8 when they went 50-32 to make the playoffs after four seasons in the lottery — dating back to the franchise’s time in Seattle. This time around, Oklahoma City spent three years out of the playoffs and looks poised to return with a higher seed in a weaker Western Conference.

Despite losing Tuesday’s showdown with the Timberwolves, the Thunder still boast the West’s best point differential at plus-7.7 per game (third in the NBA). Oklahoma City has certainly benefited from improbably hot 3-point shooting. The Thunder lead the NBA at 40% beyond the arc, up from 36% a year ago (17th). Rookies Cason Wallace (59%) and Chet Holmgren (43%) are both outpacing their college 3-point shooting, which is unlikely to continue.

Defensively, Oklahoma City has most outperformed opponents’ shot quality among this group of teams. The Thunder’s qSQ ranks 12th in the league, while they are actually third in opponent eFG% behind Minnesota and Houston. Only the Pelicans have seen opponents underperform their expected shooting outside the paint more. Given Oklahoma City’s poor defensive rebounding, this projects as a below-average defense going forward.

Based on those factors, I don’t think the Thunder are as likely to claim home-court advantage in the first round as Minnesota. Still, Oklahoma City has put itself in excellent position to qualify for the playoffs without having to go through the play-in, which would be a major accomplishment.

Orlando Magic

The Magic (along with the Phoenix Suns) share the NBA’s longest current winning streak at seven games as they’ve moved into a top-four spot in the East alongside the three teams who finished atop the conference last season (Boston, Milwaukee and Philadelphia). With an average age of 24.9, Orlando is the league’s fourth-youngest team, but has thus far improved on the 29-28 record it posted from Dec. 7 to the end of last season.

Unlike the other surprise teams near the top of the NBA in defense, the Magic are doing this despite opponents shooting around league average against them. Orlando’s stout defense is built on the unlikely combination of the league’s No. 1 turnover rate and No. 2 defensive rebounding rate. No team has finished in the top two in both categories since the 1984-85 Philadelphia 76ers, who also did so in 1982-83 en route to the championship.