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,1 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.
Allen has eschewed some of his jumpier tendencies from the early parts of his career, when savvy post men could fake him up into the air too easily. He regularly stays grounded, using his length more effectively.
Rim protection, though, is more than just what happens on attempts near the hoop; it’s also about deterring the opponent from getting there in the first place.
Gobert’s track record here is hard to believe. Every single year of his career, despite changing personnel around him, the Jazz have allowed a lower percentage of opponent shots at the rim with the Frenchman on the floor than off; those shots instead come largely from less efficient midrange areas.
Allen doesn’t have those sort of eye-popping deterrence splits yet. But he’s never played in a drop scheme as pronounced as Utah’s with Gobert, and there’s plenty of context at play in on/off-court numbers.
Both are long and mobile enough to hold their own defending in space, a must in the modern league even if you’re an elite rim protector. (Just ask Roy Hibbert.) Gobert, long underrated in this area, holds the league’s lowest efficiency mark allowed on isolations by smaller players (guards and forwards) among centers who have been regularly targeted2 since the 2019-20 season, per Second Spectrum; Allen is closer to league average in that period, which will do just fine when you protect the paint like he does.
In a game that still relies on shots at the rim, these are two of the best at preventing them. It’s no surprise that broad defensive metrics recognize their value.
Alex Caruso, Chicago Bulls
3rd in D-RAPTOR; 7th in D-EPM; 27th in D-LEBRON
Matisse Thybulle, Philadelphia 76ers
5th in D-RAPTOR; 12th in D-EPM; 31st in D-LEBRON
Gary Payton II, Golden State Warriors
6th in D-RAPTOR; 2nd in D-EPM; 45th in D-LEBRON3
The rim is still the most important location in basketball, but how teams get there has changed dramatically in the past couple of decades. Defenders who can disrupt the initial action are in high demand in a league where so much offensive creation comes off the dribble.
With so many plays being initiated on the wings, turnover generation at the point of attack is wildly valuable. The NBA’s top guards in steal percentage? Payton, Thybulle and Caruso, in that order. All three are also in the league’s top five for per-minute deflections, among all players with at least 500 minutes.
Payton might be the purest ball-hawk among them, and maybe in the entire league. One lazy dribble around this guy is too many.
Caruso, meanwhile, is a screener’s worst nightmare. He navigates picks as well as anyone in the NBA, constantly appearing in the ball-handler’s line of sight earlier than anticipated to cause problems:
Caruso wears offenses down with his persistence. Screeners, sick of dealing with him, alter their timing or positioning, playing right into his hands. He is third among all NBA players with at least 500 minutes in rate of non-charge offensive fouls drawn, per PBPStats.com. Most of those are illegal screens.
While Caruso and Payton spend most of their time on guards, Thybulle’s common matchups range from Steph Curry and Zach LaVine to Jayson Tatum, Kevin Durant and Brandon Ingram; at 6-foot-5 with a 6-foot-11 wingspan, he was bound to be used by Doc Rivers in a more versatile role.
Thybulle is one of the league’s best at jumping passing lanes for steals, and his ability to recover and contest shots is remarkable:
These three are by no means an exhaustive list of elite ball stoppers in the NBA. The imperfect nature of available defensive metrics, especially for perimeter defenders, means it’s no guarantee that some of the most respected ball hawks in the league will show up near the top. But that these three consistently top this season’s varying all-in-one metrics is at least some signal of their status in helping define this archetype.
Draymond Green, Golden State Warriors
T-8th in D-RAPTOR; 1st in D-EPM; 2nd in D-LEBRON
Evan Mobley, Cleveland Cavaliers
T-21st in D-RAPTOR; 4th in D-EPM; 6th in D-LEBRON
What earlier iterations of the NBA may have called tweeners, these players are known by today’s league as versatile stoppers who play shifting roles in their teams’ defense.
Green essentially invented this archetype and remains its embodiment. He is perhaps history’s most atypical combination of unusual athleticism (limited vertical leaping ability and height but uber-long arms and startling lateral mobility) and elite basketball IQ.
Green’s raw rim protection numbers aren’t typically quite in the Rim Behemoth tier, though he’ll have years when he approaches that range. He leans more toward the deterrence end, with a consistent history of suppressing opponent rim attempts at a level that nearly rivals Gobert in terms of on/off impact — largely through leveraging his sky-high smarts to snuff out actions in advance.
That IQ is even more visible in his transition defense. Green is always thinking a step ahead, calling out positioning to teammates and influencing the play with his movements. His hands are excellent; he positions himself ideally, demonstrating a willingness to take charges; he’s perfected the art of contesting vertically at the rim despite backward momentum. Year after year, the Golden State Warriors allow opponents fewer transition attempts and a lower efficiency on the fast break with Green on the court than off. It simply can’t be coincidence.
Mobley, meanwhile, is what the term “unicorn” is meant for in sports. At 20 years old and in his first pro season, it’s obvious watching him that he’s still learning the nuances of NBA defense — and yet he’s a consensus top-15 impact defender in all our metrics.
Rim protection? Easy. Mobley is allowing a field-goal percentage of 52.5 as the primary rim defender, one of the 15 lowest numbers in the league (among players with at least 100 field goals defended) — just decimals below teammate Allen and on more attempts against.
Defending in space? Not a problem. Guards can sometimes beat him with a quick first step, but he’s so long and fluid that he’s often back in the picture before they expect it:
The Cleveland Cavaliers allow under 0.8 points per chance on any possession featuring an isolation against Mobley that ends in a shot, foul or turnover, per Second Spectrum; that number is still elite even when filtered only for quicker guards like LaVine, Trae Young or Devin Booker. He’s already a fully switchable weapon.
Cavs coach J.B. Bickerstaff has even experimented with Mobley as the top-of-the-key hub for Cleveland’s occasional zone defense. The numbers are uneven — largely because, again, Mobley is still learning. Still, you see possessions on which the length of Mobley and his teammates, combined with such an unusual defensive alignment, are flummoxing good offenses:
Few players in modern history, if any, have held such a high defensive ceiling at this age. His presence near the top of several quality metrics at such an early stage of his career, even as he clearly digests elements of defense in real time, should terrify 29 other teams.
While NBA defensive metrics aren’t perfect, they’re often telling us something when they all point in similar directions. This year, they’re helping show us that in today’s NBA, there’s more than one archetype that can lead a defense.
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