The Nets have the NBA's worst defense and Ben Simmons is a big reason why.
And yes, this was true before Luka Doncic turned Simmons into a break-dancing pretzel.
While his well-documented early season struggles reacclimating to the NBA have widely been tied to his lack of shooting and fear of going to the free throw line, more unexpectedly is his play on the other end.
For a player who finished second in Defensive Player of the Year voting as recently as 2021, his on-off splits, other advanced metrics, and eye test all paint the same astounding picture. For example...
- Per NBA.com, opponents are scoring 14.4 more points per 100 possessions when Simmons is playing versus when he's on the bench. That is the biggest swing of any player on the Nets.
- The 121.2 points allowed per 100 possessions in the Simmons minutes would be the worst in NBA history per Basketball-Reference.
- FiveThirtyEight's RAPTOR metric has Simmons as the no. 185 defender of the 252 players listed in its database.
How could a player as dominant as Simmons once was have dropped off so quickly on defense? There are a couple of different explanations.
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Ben Simmons simply can't stay out of foul trouble
Simmons been fouling at an insane rate, fouling out of two of his seven games in only 23 and 28 minutes of game time. That is a new trend for Simmons. He had only fouled out of six of his 309 games played before this season. He returned to lineup on Monday in a limited role and still committed three fouls in just 16 minutes.
So why is Simmons all of a sudden fouling so much? I have a couple of theories.
Theory No. 1: New NBA rules and points of emphasis
The first theory is that the rules have changed since Simmons last played, and he hasn’t become accustomed to them. The league sends out new points of emphasis that referees plan on enforcing at the start of every year, and one of the biggest areas that they’ve harped on is in freedom of movement rules.
Prior to last season, they even used Simmons as a video example for the type of physical grabbing that would be more strictly enforced.
A lot of the fouls that Simmons has been called for fall into this bucket of grabbing, pushing, or otherwise restricting movement away from the ball. He’s looked shocked that these types of calls are getting made, possibly because they weren't when he was last on the floor.
Those off-ball fouls aren’t only limited to the defensive end. Simmons already has nine offensive fouls in only seven games. Many are due to illegal screens, which were also included in the point of emphasis refereeing videos during the 2021-22 season. Karl-Anthony Towns led the league last year with 68 offensive fouls — Simmons would be on pace for 105 over 82 games.
MORE: Ben Simmons injury timeline
Theory No. 2: New teammates
Another theory is that Simmons doesn’t have any familiarity with his new teammates. They’re making basic communication errors, leading to wide open layups and bad positioning where he has to foul.
While this is certainly a shared responsibility, the Nets built their team in part around the idea that Simmons would be able to comfortably defend five positions. Brooklyn is not exactly brimming with defensive talent — especially in the front court. If Simmons can't at least partially anchor Brooklyn's defense, things fall apart fast.
Theory No. 3: New role
A third theory is that Simmons’ new role defensively is causing him to foul more. Simmons is very capable of guarding four or five positions. But he’s guarding more bigs with the Nets than he did previously in Philadelphia, where he was a devastating lockdown perimeter defender. According to Bball Index, which now lists him primarily as an Anchor Big, his time spent defending power forwards and centers has doubled since the 2019-20 season.
| Season | PG-SG-SF | PF-C |
| 2022-23 | 44% | 56% |
| 2020-21 | 68% | 32% |
| 2019-20 | 72% | 28% |
| 2018-19 | 63% | 37% |
| 2017-18 | 66% | 34% |
Whatever the reason for Simmons' fouls, it is having a major impact on the Nets' defense. They’re 25th in fouls per game and 27th in the amount of free throws they allow their opponents to shoot. Opponents are constantly in the bonus, pulling their defensive rank into the cellar.
Ben Simmons knee and back injuries are hampering his movement
When Simmons has been guarding on the perimeter with the Nets, he hasn’t looked nearly the same as in previous seasons. He used to lock down perimeter players like Luka Doncic and Trae Young in playoff series of years past. Now, he’s allowing line drive blow-bys to slower guards like Tyrese Haliburton.
Simmons has been slow to get to loose balls, he’s not jumping to contest shots very well, and he's not rotating over like he used to. He does still have great hands and instincts, allowing him to get steals and blocks. But those rates are down considerably for him as well.
A sore knee kept Simmons out of the most recent slate of Nets games until he returned to the lineup in limited minutes on Monday. That, along with a back that kept him out last year, are clearly hampering his movement.
To be fair to Simmons, the degree to which injuries have limited his defense probably should receive more attention, in the same way that nobody rightfully expected Klay Thompson to return to peak defensive form when he came back last season.
Simmons' defensive decline isn't a cause for panic yet. He deserves more patience than most have given him. Nets fans may want an instant fix, but it's going to take him a while to get his body right and learn how officiating tendencies have changed during his absence.
