For much of NBA history, building an elite defensive team came down to simply employing one of the league’s handful of generational defensive bigs.
Bill Russell’s Boston Celtics regularly lapped the field defensively. David Robinson instantly made San Antonio a top-three defense during his rookie season in 1989-90; the Spurs wouldn’t dip below the top 10 again until Robinson played just six games in the 1996-97 season due to injury. Alonzo Mourning’s Miami Heat, during his first run with the team from 1995-96 through 2001-02, never finished worse than eighth in the NBA in per-possession defense.
With some exceptions, defense in the NBA has run primarily through big guys. But modern pace-and-space developments, combined with unique athletic profiles and a shifting understanding of the game, may have changed this in recent years — and the evidence can be seen in some of the best defensive metrics available today.
FiveThirtyEight’s defensive RAPTOR, Dunks & Threes’ defensive Estimated Plus-Minus and BBall Index’s D-LEBRON metrics all feature some of the same names atop their defensive leaderboards. While such metrics share certain broad similarities in the way they’re calculated, they differ in terms of specific variable weights. For this reason, it’s often meaningful when quality metrics with different inputs are arriving at similar conclusions.
Some of the consensus names on the 2021-22 leaderboards for these metrics, through games of Jan. 30, are instructive in the way they represent the evolving world of NBA defense. They reveal multiple player archetypes around which a modern defense can be built, offering alternatives that likely weren’t as realistic at other points in league history. And while positional versatility and switchability are big parts of this evolution, it still begins in the paint.
Traditional Rim Behemoths
Rudy Gobert, Utah Jazz
1st in D-RAPTOR; 9th in D-EPM; 1st in D-LEBRON
Jarrett Allen, Cleveland Cavaliers
10th in D-RAPTOR; 10th in D-EPM; 7th in D-LEBRON
You can talk about modern spacing and shooting until you’re blue in the face, but a simple fact remains: The most valuable shots in the NBA still take place at the rim.
For the 2020-21 season, in play outside of garbage time and the last possession of each quarter, attempts within 4 feet of the basket were worth 1.28 per shot — the most of any shot location. Even corner threes, those bastions of analytics-focused offenses, were worth fewer points at 1.18 per shot, according to data from Cleaning the Glass. The game’s best rim protectors, therefore — those capable of staying on the floor even as the game evolves — still hold massive value.
Gobert has long been the gold standard barricading the basket. He’s allowed a field-goal percentage of no more than 51 percent at the rim in this season and each of the past two, per Second Spectrum data on NBA.com, and sits in rarified air below 50 percent so far this year. The Jazz’s primary defensive scheme against pick and rolls, which drops Gobert back into the paint and often tasks him with tracking both ball-handler and roll-man while teammates stay home on spot-up shooters, is tailor-made to his generational length and mobility.
Allen is also in the NBA’s top 15 in stinginess among high-volume rim protectors this season; opponents have shot less than 55 percent against him in each of his five seasons. He is used in a larger variety of schemes than Gobert, and he isn’t far behind for raw rim defense numbers.
To the extent post play is still utilized in today’s league, it’s mostly useless against these guys. Teams have realized it with Gobert: He has defended just 14 post plays that ended in a shot, foul or turnover all season, per Second Spectrum, and six of those were via Nikola Jokić or Joel Embiid — the only sort of players who should be trying.
Opponents attack Allen in the post more often, maybe because they haven’t updated their scouting reports. He was sieve-like on the block early in his career; that’s no longer the case.