The Whiteboard: Power ranking the NBA’s best defenses

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The 2021-22 NBA season is still very young — most teams have only played about 10 games thus far — but we’re already starting to see separation among the good and bad. This has been especially true on the defensive end where a spread of 16.4 points per 100 possessions separates the best defensive in the league from the very worst. In addition, we’ve seen defense emerge as an Achilles’ heel for some teams, like the Hornets (30th inf defensive efficiency) and Knicks (27th), who got off to hot starts but have begun to fade back into the pack.

At the other end of the spectrum, we some unexpected teams ranked in the top five in defensive efficiency. Previous research has identified 16 games as the point at which a team’s defensive rating generally passes at least a 0.500 correlation threshold with its end-of-season mark. That is to say that we can feel pretty confident that even if these teams don’t have the best have the absolute best defenses in the league by the end of the year, they’re still likely to be very, very good.

Which teams have had the NBA’s best defenses thus far?

5. Washington Wizards — 103.1 points per 100 possessions

This is a massive improvement for a team that finished 20th in defensive efficiency last season, surrendering an average of 112.3 points per 100 possessions. They’re likely benefiting from some early good luck — opponents have made just 33.0 percent of their wide-open 3-pointers against the Wizards, an unsustainably low number that’s likely to go up. But the additions of Spencer Dinwiddie and Kentavious Caldwell-Pope have been big upgrades to their perimeter defense and their getting solid contributions from young players like Deni Avdija and Daniel Gafford. They don’t foul, they’re reasonably solid on the defensive glass and even if they’re hit by some progression to the mean on their opponents’ shooting percentages they should still finish well above league average in defensive efficiency.

4. Miami Heat — 101.3 points per 100 possessions

The Heat were already a strong defense, finishing 10th in the league last season, but swapping Kyle Lowry in for Goran Dragic is a huge and obvious defensive upgrade. They have some weaker defenders playing big minutes for offensive reasons but their chemistry, skill and aggressiveness of Bam Adebayo, Jimmy Butler and Lowry is a heck of a defensive scaffolding. In the 138 minutes that trio has been on the floor together, the Heat have allowed just 97.8 points per 100 possessions. A deep playoff run may ask a lot from that trio on defense but they certainly seem up to the challenge.

3. Los Angeles Clippers — 100.4 points per 100 possessions

The Clippers have lost two of the best perimeter defenders in the league from last season’s rotation — Kawhi Leonard (injury) and Patrick Beverley (trade) — but they’ve still been able to make a huge jump at that end of the floor. Eric Bledsoe and the continued emergence of Terrence Mann has helped but this is simply a roster loaded with long, aggressive ballhawks. They are fourth in the league in opponent turnover percentage and they have six different players in their regular rotation averaging at least 1.0 steals per game — Bledsoe, Mann, Paul George, Nicolas Batum, Marcus Morris and Isaiah Hartenstein. Their length has also helped them challenge shots — they have allowed among the fewest wide-open 3-pointers in the league and they rank third in defensive field goal percentage in the restricted area, despite playing without a traditional rim protector.

2. Denver Nuggets — 100.1 points per 100 possessions

On paper, the tandem of Nikola Jokic and Michael Porter Jr. should make the Nuggets an offensive powerhouse with a weakness at the other end of the floor. But thus far, the Nuggets have been keeping their heads above water with the second-best defense in the league. They rank in the top 10 in all of the defensive Four Factors — the force misses and turnovers, don’t foul and crash the defensive glass. And even though their offense is struggling they’ve been able to keep their opponents from taking advantage in transition — allowing one of the lowest fastbreak point averages in the league and forcing their opponents into some of the longest offensive possessions in the league. Of all the top five marks, this feels the most fragile given that the roster doesn’t really have any elite individual defenders. But for now, it’s working.

1. Golden State Warriors — 97.0 points per 100 possessions

If you guessed the Warriors would have the best defense in the league at this point in the season, and by a significant margin, you were probably part of a very small group. Klay Thompson still hasn’t returned and guards like Damion Lee and Jordan Poole, who aren’t exactly elite defenders, have been sopping up those minutes. And Kevon Looney is the only traditional big man in their rotation which means Draymond Green, a stretch big like Nemanja Bjelica or wings like Andrew Wiggins or Otto Porter Jr. have been playing most of the center minutes. The Warriors are another team that is likely to be hit by some progression to the mean in their opponent’s shooting percentages — so far opponents have made just 71.8 percent of their free throws and 31.1 percent of their open and wide-open 3s against the Warriors.

But they’ve been thriving with their small-ball lineups and, like the Nuggets, rank in the top 10 in all of the defensive Four Factors. Among the most impressive mark is them leading the league in defensive rebound percentage despite their consistently and unconventionally small lineups. Thompson’s return won’t solve their size problems but he’s another strong wing defender that should help them build on what’s become an entirely unexpected strength.