Defensive Metrics Don’t Ever Agree … Except On Rudy Gobert’s Great Season

End-of-year NBA awards are a good lens through which to evaluate the league’s best performances, but the framing isn’t always quite right. Certain seasons are so exemplary that viewing them only in the context of same-year contemporaries sells them badly short.

The 2020-21 Defensive Player of the Year Award serves as one such instance. While his competitors may disagree, the data suggest that not only is Utah Jazz center Rudy Gobert running away with this year’s award, he’s having one of the best defensive seasons in modern NBA history.

The broad indicators bear this out. Gobert’s play is the primary driver behind Utah’s top-ranked per-possession defense outside garbage time. This season, the Jazz are 11.9 points per 100 possessions better defensively when the Frenchman plays compared with when he sits, per Cleaning the Glass. That’s the largest such gap in the NBA among players with at least 1,000 minutes. In fact, Gobert’s defensive on-off split is one of the largest of any high-volume player over the past 15 years:

Raw on/off figures, though, don’t account for additional context like teammate or opponent performance, which can be significant. Fellow Jazzman Mike Conley, for instance, holds the NBA’s second-highest defensive on/off differential this year among those high-volume players — but that’s partially because Conley has played over 90 percent of his minutes alongside Gobert.

Luckily, more robust metrics can fill in these contextual gaps, combining box score numbers with play-by-play information, on/off metrics and — in some cases — camera-driven player tracking data. We’ll use FiveThirtyEight’s defensive RAPTOR, ESPN’s defensive Real Plus-Minus, Dunks & Threes’ defensive Estimated Plus-Minus and BBall Index’s D-LEBRON metric to try to define the best defensive seasons in their samples. (A couple of these span only the past decade or two; others go back much further.)

Several consensus all-time defensive greats show up among the best seasons tracked by one metric or another, but no single player-season is quite a consistent presence atop all of them. No single player-season, that is, except Rudy Gobert’s 2020-21 campaign.

“I think it goes way deeper than the box score,” Gobert told FiveThirtyEight, speaking of modern analytics, which both he and the Jazz are open about embracing. “I think those metrics, which are all different but all similar in a way — when you combine all of them, I think you have a pretty precise idea of how a player impacts the game of basketball on the court.”

Gobert’s consistency across metrics stands out. Each of them is calculated with different variables and weights; a quirk in one could, theoretically, inflate a given player’s value somehow. Gobert’s current campaign rating at or near the top of every single one is hard to ignore, especially with so many of the game’s defensive greats sitting alongside him.

The picture is the same when looking at situational data. The pick and roll is much of the league’s bread and butter, easily its most common offensive play type, and no one shuts it down like the Stifle Tower. Per Second Spectrum tracking data, when Gobert defends a pick-and-roll screener, the offensive team scores just 0.851 points per chance — the lowest number among the 65 centers who have defended at least 300 such plays this season. Gobert has the length and mobility to effectively guard two players at once:

Year after year, with remarkable consistency, Gobert bends opposing shot charts simply by defending the pick and roll. Opponents shoot far less at the rim but also can’t get open 3-point looks because of how he allows Jazz perimeter defenders to stay home on their men — the result is too much reliance on inefficient midrange shots the Jazz are happy to concede. That effect has been even greater this season.

To their credit, opponents have largely stopped attacking Gobert in his de facto office. Just one player in the entire league has attempted more than 10 post-ups against him this year (Jonas Valančiūnas). Gobert is on the extreme end here — not surprising, given how inefficient post-ups on him are — but the league has collectively realized that post play has limited efficacy on the whole. Per Second Spectrum data, total league-wide post-ups have declined in each of the past eight seasons. Stalwart defenders like Gobert make it a silly exercise even for some of the bulkier, skilled big men in the game, and he’s not the only 7-footer who has seen his post defense duties diminish in recent years.

A word of advice: If your name isn’t Jokić or Embiid, you shouldn’t be posting this guy up.

Gobert’s pick-and-roll and post defense success isn’t breaking news to keen NBA observers. Quietly, though, he’s become a much more well-rounded defender in a league that’s turned ground-bound paint protectors into dinosaurs over the past half-decade.

“I’ve gotten much more comfortable over the last few years guarding shooting bigs and guarding on switches,” Gobert said. “All the numbers back it up. It’s not just me saying that.”

For the 2020-21 season, opponent possessions featuring an isolation with Gobert as the primary defender have yielded 0.779 points per chance. That’s fourth-lowest in the NBA among 66 players who have defended at least 125 isolations, per Second Spectrum data, trailing only Draymond Green, Richaun Holmes and Julius Randle — and a big improvement from earlier in Gobert’s career.¹

A half-decade-old viral clip of Steph Curry turning a younger Gobert around off the dribble has shown remarkable staying power; once or twice a game, some unsuspecting young guard gets Gobert on a switch and assumes it’s easy pickings, only to be rudely awakened to the reality:

Smarter offenses eschew the iso against Gobert, generally in favor of attempting to stretch him out utilizing modern spacing and shooting themes. A ball-handler who can pull up for three, a stretch big man or even both simultaneously can force contortions away from the Jazz’s preferred drop-big defense.

He’s improved here too, though, both in terms of effectiveness and willingness. Today’s Gobert will often play up higher in pick and rolls against known pullup aficionados like Damian Lillard or Devin Booker — but he also has the mobility to recover all the way back to the rim and put out any fires this increased floor space creates:

“He’s able to close out, run across the court, block a shot,” said Jazz coach Quin Snyder. “His ability to make multiple plays, I think, is unique — for any player, but particularly for a center.”

This season, Gobert’s 0.868 points allowed per chance on closeouts is the single lowest in the NBA among 39 centers with at least 150 closeouts, per Second Spectrum tracking.

“When I knew that teams were completely changing their way of attacking me, either by changing who they play or changing how they play offensively to try to take me out of my comfort zone, I realized that I have to be comfortable anywhere,” Gobert said.

This wasn’t an easy, or short, process. Snyder and staff have worked with Gobert for years on skills that will help him keep pace with a faster, guard-heavy league. Gobert admits to studying extensive film of many all-time defensive greats, especially in his younger days — even if he prefers not to be compared directly to them. “I think everyone is different and everyone is unique,” he said.

Still, he’s learned from the Olajuwons, the Russells, the Wallaces. Their defensive mindset, as much as anything, is one he aspires to. This season, at least, it’s fitting these legends might be some of his only true defensive comparables.

“The day I retire, we’re going to be able to look at the data,” Gobert mused. “I think that day, maybe people will finally stop disrespecting me and realize. Until then, it’s a blessing to be able to be mentioned with all those great names.”

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