Exposing the NBA's Worst Defenders This Season
Even in this age of NBA information, when everyone has access to deep-dive numbers that even front offices weren't privy to a decade ago, accurately measuring defensive impact remains an unconquered frontier.
In its explainer for box plus/minus ("a basketball box score-based metric that estimates a basketball player's contribution to the team when that player is on the court"), Basketball Reference acknowledges some of the limitations of defensive catch-all numbers.
"Such critical components of defense as positioning, communication, and the other factors that make Kevin Garnett and Tim Duncan elite on defense can't be captured, unfortunately. ... Box Plus/Minus is good at measuring offense and solid overall, but the defensive numbers in particular should not be considered definitive. Look at the defensive values as a guide, but don't hesitate to discount them when a player is well known as a good or bad defender."
For this exercise, we'll deploy three such guides (defensive box plus/minus, Dunks & Threes' defensive estimated plus-minus and 538's defensive RAPTOR rating) and defensive rating (a team's points allowed per 100 possessions when a given player is on the court) to give us an idea of who's been the biggest liability on that end in this early portion of 2021-22.
When you sort every player with 100-plus minutes by the average of their ranks in those four numbers, you get the following top five: Gary Payton II, Isaiah Hartenstein, Andre Iguodala, Nikola Jokic and Giannis Antetokounmpo.
One eyebrow-raiser there might be Hartenstein. And though his numbers may return to earth a bit over the course of the season, the Los Angeles Clippers are allowing a whopping 12.8 fewer points per 100 possessions when he plays. Other than that, the top five passes the sniff test (misconceived notions about Jokic notwithstanding).
Of course, this isn't a perfect exercise. Each number has its shortcomings, and defensive rating is largely dependent on who the player is sharing the floor with. But these guides, in concert with video and a handful of other numbers, at the very least, point us in the right direction.
And on the opposite end of the aforementioned top five, below you'll find the bottom of the list.
For years, Tristan Thompson was known as a solid defender who could dominate the glass, block a few shots and generally be in the right spots on that end of the floor.
Contrary to that reputation, however, Thompson's teams have allowed more points per 100 possessions when he's been on the floor in eight of his 11 seasons. And the bottom appears to have fallen out of that number in 2021-22.
This season, the Sacramento Kings are allowing 120.5 points per 100 possessions (a mark that ranks in the third percentile) when Thompson plays, compared to 110.1 when he doesn't.
While there are other contributors to that mark, as a center, Thompson is ostensibly the anchor of units he's in. And he's offering little resistance inside.
When defended by Thompson, opponents are shooting 55.4 percent from the field, compared to an expected field-goal percentage of 47.9.
Very few can get a handle on the speed and size of players, not to mention the complexity of defensive schemes, during their first NBA season. Evan Mobley is the exception to the rule that most rookies just aren't very good on defense.
So, Jalen Green finding himself on a list like this after roughly a quarter of his first season shouldn't ring many (if any) alarm bells.
But he's here. And when you look at his individual numbers, it's not hard to see why.
When Green is off the floor, the Houston Rockets are giving up 102.3 points per 100 possessions, a mark that would rank behind only the Golden State Warriors' 100.4. When he's playing, Houston's defensive rating blasts up to 114.2.
Of course, that's not really a fair comparison. Most of Green's possessions are played against starters. Those non-Green lineups are often deployed against reserves. But that big of a swing is worth noting.
A lack of basic defensive numbers also contributes to the rookie's rank. Among players with at least 200 minutes this season, there are just seven who have a defensive rebounding percentage below 10.0, a steal percentage below 1.0 and a block percentage below 1.0.
Green, of course, is there.
All the same "don't worry, he's a rookie" caveats apply for Ziaire Williams, the Memphis Grizzlies' first-year reserve wing who's averaging 2.5 defensive rebounds, 0.9 steals and 0.6 blocks per 75 possessions.
Any of those numbers on their own (with the possible exception of the defensive rebounds) wouldn't be that big of a deal. Together, they paint a picture of someone who's doing very little to move the needle in the right direction on defense.
Low box score marks aren't necessarily indicative of bad defense. Remember our discussion from the intro. Defensive catch-alls are a guide. Klay Thompson is an example of someone whose prowess as a perimeter defender was not captured by blocks, steals or rebounds.
But for Williams, at least for now, there's no reputation to offset the bad numbers. Memphis, which is dead last in defense (by a long shot), is significantly worse when Williams is on the floor. Opponents exceed their expected field-goal percentage when he's defending. And there isn't a single catch-all that views him as a replacement-level defender.
There's a lot working against D.J. Augustin on the defensive end.
First, he's on a bad defensive team that's almost entirely devoid of players who can cover up his weaknesses. For years, Rudy Gobert has made subpar defenders look OK statistically, just because he wipes so many points off the board. There is no such help for Augustin from the Houston Rockets.
It's tough to blame him for the other problems too. Everyone slows down a bit with age, and Augustin is 34 years old. Standing 5'11" is a natural disadvantage too. Even the scrappiest under-6-foot players simply cannot make up for their lack of size in certain matchups.
On the occasions he is able to keep his matchup in front of him, players of an average (or near-average) NBA height can simply shoot over the top of Augustin.
All of the above adds up to dreadful defensive numbers, including Houston allowing 11.3 more points per 100 possessions when Augustin is on the floor and opponents shooting an astronomical 13.4 points better from the field when he's guarding them.
Once upon a time, Terrence Ross had some decent three-and-D seasons. In fact, his teams allowed fewer points per 100 possessions when he played in five of his seven seasons prior to this one. And in 2016-17 and 2017-18, he had above-average marks in defensive box plus/minus.
But in 2021-22, everything has fallen off a cliff. Steal rate, block rate, defensive rebounding rate, defensive catch-alls, defensive rating swing. You name it, it's down. And down big.
There are a couple of possible explanations.
The first absolves Ross from some blame. As has been mentioned a few times, defensive catch-alls can contradict reputation. And when you watch Ross, there are still moments you see the wing with decent size and athleticism who can bother opponents.
Bad teammates could be contributing too. The Orlando Magic have the worst bench in the league. And four bad defenders dragging one decent one down is a far likelier outcome than one decent defender saving a unit that's a last-place minus-8.3 points per 100 possessions.
It's probably not fair to default to that explanation, though. There should be some responsibility on the part of Ross. And from a 30-year-old heat-check-off-the-bench gunner on a tanking team, protracted stretches of disinterested defense aren't surprising. And that's exactly what Orlando is getting from Ross.
If the Magic move him to a playoff team (or contender) at some point this season, we may see some renewed effort from him. But right now, Ross looks checked out.