Metrics 101: Exposing the NBA's Worst Defender at Every Position

Contrary to popular belief, NBA players do actually play defense. 

The rules are set up to favor offensive players, especially now that freedom of movement is encouraged and defensive schemes are still scrambling to account for the plethora of threes fired up on any given night.

Good offensive players will always have an inherent advantage, as they force even the league's most skilled stoppers to react rather than force the reactions. The skill level throughout the Association has also risen to stratospheric levels. 

But again, almost everyone actually plays defense.

Unfortunately, these five featured players don't help advance the argument. They still succeed on some possessions, but undisciplined play, incompetence in pick-and-rolls and general lethargy in off-ball scenarios take priority almost every night. They're indisputable liabilities on the less glamorous end. 

To choose them in objective fashion, we're turning to a trio of defensive metrics: Basketball Reference's defensive box plus/minus (DBPM), ESPN.com's defensive real plus/minus (DRPM) and Basketball Index's defensive player impact plus-minus (D-PIPM). No singular metric can perfectly encapsulate defensive play, but grading out poorly in each of these three overarching numbers tends to be a clear-cut indication of lackluster performance. 

So that we can standardize between three different grading systems, we're looking at every NBA player with at least 200 minutes and then finding the Z-scores for each of them in each of the three metrics. Summing those scores gives us the overall number listed parenthetically next to each of our featured sieves. 

Here's hoping your favored franchise doesn't have any representatives. And here's definitely hoping your favored franchise isn't the one with two. 

DBPM: minus-3.1

DRPM: minus-4.66

D-PIPM: minus-2.9

Though Trae Young has begun to catch fire for the Atlanta Hawks, making good on his awe-inspiring offensive potential in recent weeks as the game seems to slow down for him, the first-year point guard hasn't experienced similar improvements on the defensive end. He's still a glaring liability for a porous Hawks defense, incapable of navigating screens at the top of the key, handling switches or remaining focused in off-ball circumstances. 

Maybe he'll be better in future seasons as he makes further adjustments to the speed of the Association and begins to understand some of the schemes being used against him. But even playing mediocre defense would require a quantum leap; he's that bad right now, checking in dead last by a significant margin in DRPM and showing precious few signs that future growth is likely. 

To be fair, Young's point-preventing ceiling is inherently limited by his frame. During the 2018 combine, he stood a half-inch above the 6-foot threshold with a wingspan that checked in at only 6'3", per NBADraft.net. Without lanky arms or the size necessary to contest shots against even the league's smaller 1-guards, there's only so much he can do. 

But tiny floor generals have used savvy positioning to make positive impacts in the past. Even Isaiah Thomas once put together some solid displays during his time with the Sacramento Kings, intuitively jumping passing lanes and remaining active away from the primary action. Young, to this early point in his professional career, simply doesn't seem to have those instincts as he makes the Atlanta defense a rotation-worst 8.6 points per 100 possessions worse when he's on the floor. 

Dishonorable Mentions: Collin Sexton (minus-6.635), Jamal Crawford (minus-6.35), Quinn Cook (minus-5.031), Frank Jackson (minus-4.998), Derrick Rose (minus-4.877)

DBPM: minus-3.0

DRPM: minus-3.24

D-PIPM: minus-3.8

We're admittedly fudging a little bit here by calling Devin Booker a shooting guard during his 2018-19 efforts for the Phoenix Suns. Though Basketball Reference indicates that he's spent 80 percent of his minutes at the 1, Cleaning the Glass—which, subjectively, seems to be more accurate in this area—provides the second opinion and shows that 50 percent of his run has come at the smallest spot in the lineup. 

But Booker should still be considered a long-term 2-guard in the desert, as that remains his natural position—the spot at which the team should intend to play him when it finally finds a foundational point guard for the seemingly perpetual rebuild. Plus, his time defending opposing floor generals serves as a notable reason he grades out so poorly in this exercise. 

Booker has always functioned as a lackluster defender, but he's been particularly bad navigating pick-and-roll sets against opposing guards who have a slight speed advantage. Unable to make that split-second decision about fighting over the top or ducking underneath the screen, he's ceded enough space that he constantly gives up open shots or ends up trailing his man en route to the painted area. 

And yet, focus may still be the primary issue here. Or really, a lack of focus. 

During previous seasons, Booker has operated as a notorious ball-watcher in situations away from the primary action, and that hasn't changed in 2018-19. He can routinely lose track of his own assignment in favor of ill-advised gambles into passing lanes, and his movements sometimes border on apathetic.

Perhaps that will change when the Suns are ready to compete for something of significance, but it's already a habit that needs breaking for an athletic 22-year-old who ranks first on his team in minutes per game but No. 12 in deflections per contest and No. 10 in contested shots per night. 

Dishonorable Mentions: Jordan Clarkson (minus-6.119), Marco Belinelli (minus-5.605), Antonio Blakeney (minus-5.592), Malik Monk (minus-5.121), Lou Williams (minus-4.916)

DBPM: minus-2.5

DRPM: minus-3.49

D-PIPM: minus-1.8

That Kevin Knox needs to work on his defense isn't exactly a surprise.

That was the big knock on his game prior to the 2018 NBA draft, and it's remained his biggest bugaboo despite shooting only 36.2 percent from the field throughout his initial campaign. New York Knicks head coach David Fizdale didn't mince words on the topic in late December, per Stefan Bondy of the New York Daily News: 

"I'm really looking at his defense and his rebounding. Those are the other areas that I'm really hammering on. The scoring, I'm telling you this kid is just going to get better and better at the scoring because he's a natural with that. But what we're really harping on him with his is defending and rebounding. Those are the things we're really drilling."

Since that article's publication, the Knicks have allowed 105.9 points per 100 possessions without the 19-year-old on the floor. When he plays, that defensive rating skyrockets to a putrid 112.1—an effect that can be attributed to his cinderblock feet and late reactions, as evidenced by a minus-3.49 DRPM that ranks No. 88 among the 88 players listed as small forwards by ESPN. 

Positional versatility is coveted in today's NBA, but Knox's shoddy defense should earn him the dreaded "tweener" label—on that end of the floor, at least. Listed at just 215 pounds despite his 6'9" frame, he doesn't have the strength to hang with bigger forwards who bully him for deep post position or the foot speed necessary to prevent quicker wings from blowing by him en route to uncontested finishes at the hoop. 

Dishonorable Mentions: Cedi Osman (minus-4.803), E'Twaun Moore (minus-4.662), Kelly Oubre Jr. (minus-3.735), Taurean Prince (minus-3.622), Alfonzo McKinnie (minus-2.675)

DBPM: minus-1.8

DRPM: minus-1.72

D-PIPM: minus-1.6

Usually, big men are supposed to find more success on the defensive end during their sophomore seasons. But the opposite has been true for John Collins, who looked like a promising stopper as a rookie for the Atlanta Hawks before his effectiveness plummetted in 2018-19. Take a quick gander at his two-year progression in each of the three notable metrics: 

• DBPM: 1.9 in 2017-18; minus-1.8 in 2018-19
• DRPM: 1.05 in 2017-18; minus-1.72 in 2018-19
• D-PIPM: 0.7 in 2017-18; minus-1.6 in 2018-19

So, what gives? What's to blame for the sudden and dramatic drop-off? 

In a word: schemes. 

Collins is spending more time operating at the 4 next to a traditional center, which forces him to the perimeter and away from his areas of strength. He doesn't look comfortable jumping into passing lanes when starting outside the painted area, whereas he demonstrated some solid rim-protection skills as a rookie who averaged an additional 0.3 steals and 0.7 blocks. He also fails to show proper help instincts, possibly because he was often the primary interior defender in 2017-18. 

This year, he's allowed opponents to shoot 62.6 percent at the tin while facing 4.7 shots per 36 minutes; last year, those numbers stood at 58.7 and 6.8, respectively. Meanwhile, he's earning 0.7 fewer deflections and 3.0 fewer contested shots per 36 minutes, indicating less involvement on the defensive end—and, when he does get involved, he's doing so against players who tend to operate more on the perimeter, where he's far less fluid. 

As a rookie, Collins' biggest defensive issue was that he drew too many whistles. Now, he's remedied that flaw without fixing what forced the fouls in the first place: slow feet on the perimeter that allow blow-bys, which he often attempts to negate with his prodigious athleticism. Atlanta isn't helping him, either. Forcing him to spend more time at the 4 and switch onto guards more frequently has only compounded his struggles. 

Dishonorable Mentions: Bobby Portis (minus-3.104), Patrick Patterson (minus-2.775), Jeff Green (minus-2.588), Markieff Morris (minus-2.295), Julius Randle (minus-2.085)

DBPM: minus-0.1

DRPM: minus-1.46

D-PIPM: minus-1.7

Were it not for the defensive rebounding numbers that boost his DBPM into more palatable territory, Enes Kanter would emerge with an even worse score in this analysis. But based both on his work with the New York Knicks and his short tenure with the Portland Trail Blazers, he still doesn't have any trouble earning the featured spot for centers. 

This shouldn't come as much of a surprise. Kanter has functioned as a defensive liability for years, attempting to overcome his uninspired, stuck-in-molasses play on the preventing end with tenacity on the glass and tremendous touch around the basket. He might hemorrhage points, but he can often make up the lost ground with sheer offensive firepower. 

Still, wouldn't it be great if such a trade-off weren't necessary in the first place? 

Kanter can't be pleased that even Devin Booker, who knows a thing or two about lackluster defense, has poked fun at his porosity. But he's deserved the barbs.

Leaving the 6'11" center alone in the painted area isn't a recipe for disaster. He's willing to contest shots and play physically on the interior, even if he's liable to give up quite a few easy buckets. It's when he's dragged out of the restricted area that he becomes a true turnstile, and it's increasingly easy to force that development in an NBA defined by five-out offensive sets with floor-spacing acumen at every position. 

Put Kanter in a pick-and-roll, and he'll conflate disparate coverages before picking the wrong one and betraying his teammates with athletic disadvantages. Ask him to guard an isolation set, and his compatriots may as well shield their eyes from the ensuing carnage. Worse still, opponents understand these limitations and frequently target him—the strategy to which Booker was alluding. 

The Knicks were 3.9 points per 100 possessions worse on defense when he played. Admittedly with quite the small sample, Rip City's defensive rating has fallen by 11.8 when he's logging minutes.

Based on his lengthy history as a weak link in the defensive chain, don't expect that trend to change anytime soon. 

Dishonorable Mentions: Willy Hernangomez (minus-1.925), Meyers Leonard (minus-1.078), Kenneth Faried (minus-0.855), Jahlil Okafor (minus-0.727), Tristan Thompson (minus-0.635)

Adam Fromal covers the NBA for Bleacher Report. Follow him on Twitter, @fromal09.

Unless otherwise indicated, all stats accurate heading into games Feb. 28 and courtesy of Basketball Reference, NBA.com, PBPStats.com, NBA Math or ESPN.com.