The NBA rules regarding what defenses are considered illegal are arguably some of the most important rules in the game, since they can completely shift the offensive and defensive balance and how teams strategize. Recently, the NBA’s illegal defense rules have changed significantly — and keeping up with these changes is crucial to understanding games.
Most of the NBA’s current rules against illegal defenses concern different types of player fouls. As you’re watching your next NBA game, you’ll want to look out for defense violations like charges, intentional fouls, and blocking fouls to see if you can spot and identify them.
In this article, I’ll be explaining what exactly ‘illegal defense’ means when it comes to the NBA rules and whether they still apply to present-day games. I’ll also be listing all of the types of illegal defenses you need to be aware of, and explaining how the NBA has changed over time due to these rules. Here’s everything you need to know about NBA illegal defenses.
What Is Illegal Defense in the NBA?
Illegal defense is a category of violations that includes certain defensive strategies and several types of contact with offensive players considered illegal under NBA rules. Teams who make illegal defenses are subject to penalties like free throws for the opposing team or ball possession switches.
Presently, most defensive maneuvers considered illegal under the NBA rules are ‘fouls’ — defined as illegal contact with offensive players. Previously, the zone defense strategy was also considered an illegal defense, but the strategy has been permitted by the NBA since 2001.
Are There Still Illegal Defenses in the NBA?
Many defenses are still considered illegal by the NBA, including moves like shooting fouls and loose ball fouls. The most significant new illegal defense rule is the lane violation rule, but recent restrictions on moves like hand-checking have made playing defense considerably more difficult.
It’s clear that illegal defense rules are becoming much stricter when you look at the average offensive efficiency of league teams. The average offensive efficiency has risen as high as 112.9 in 2021 — something that the Lakers only accomplished once with Shaquille O’Neal and Kobe Bryant.
As the average offensive efficiency rises, you can reliably assume that defensive players are struggling to defend effectively while staying within NBA regulations. Worse yet, strategies like ‘drawing fouls’ have become popular with offensive players — putting defenders in a terrible position.
While restrictions on illegal defenses are still strict, the NBA has recently introduced new types of offensive fouls that seem to be resolving the issue. Defenders have taken a more significant role in games, and the average offensive rating has dropped as low as 110.5.
In many ways, the NBA seems to be returning to some of its most glorious days. Rules against strategies like flopping are being introduced to reduce false fouls, while rules against strategies like zone defense are being removed to encourage player creativity. There’s no doubt we’ll only continue to see the game change significantly in the future.
What Are the Types of Illegal Defenses in the NBA?
The illegal defenses you may observe in the NBA are blocking fouls, shooting fouls, intentional fouls, loose ball fouls, flagrant fouls, and charges. While zone defense was recently considered illegal, it’s worth noting that the strategy has been legal since 2001.
There are a few illegal defenses you’ll need to be aware of when watching your next NBA game. Here are the most common types.
- Blocking foul. Defensive blocking fouls are a type of violation that occurs when a defensive player is not properly positioned in a stationary position with both feet on the ground is stricken by an offensive player.
- Shooting foul. Shooting fouls are a type of violation that occurs when a defensive player makes a foul play against an offensive player actively attempting to shoot the basketball.
- Intentional foul. Intentional fouls are a general type of violation that occurs when another type of foul is determined to have been committed intentionally. These fouls are generally committed to give the defending team an advantage in the last minutes of the game.
- Loose ball foul. Loose ball fouls are a type of violation that occurs when the ball exits the possession of both teams. This category also includes any other general fouls committed while the ball is loose.
- Flagrant foul. Flagrant fouls are a type of violation that occurs when a player makes unnecessarily violent contact with a player from an opposing team, such as accidentally or intentionally hitting the other player in the head.
- Charge. Charges are a type of violation that occurs when a player makes extreme contact with an opposing player who is standing in place with both feet planted facing the defender, as opposed to changing courses to avoid the collision while they had time to do so.
How Did Illegal Defense Rules Change the NBA?
As they are adjusted by the NBA over time, illegal defense rules cause significant changes in the offensive and defensive balance of professional games. They influence what strategies are popularized by determining what is legal and cause shifts in average offensive efficiency.
The NBA has gone through significant changes in its illegal defense rules in almost every generation of the game. The first important change happened in 1947 when zone defense was banned to allow superstar offensive players to shine. This shaped the game as we know it today.
And when hand-checking was banned in 1979, defensive players were further weakened by their reduced ability to block offensive players. The introduction of the flagrant foul rule in 1991 also encouraged defensive players to focus on clever strategies rather than brute force.
As a result of the ban on zone defense generations before, man-to-man defense was the most popular strategy for years. Rather than assigning particular areas of the court for defensive players to guard, most teams guarded against specific opposing players by assignment.
While some teams experimented with using zone defense, it proved to be significantly less popular than man-to-man defense. The strategy is rarely seen in professional-level games due to the increased risk of lane violations, but it did prove useful for teams facing physically imposing opponents.
The most recent change to the NBA’s illegal defense rules occurred in 2022. Many players were ‘flopping’ to bait referees into calling falsified fouls, and it was completely changing the pace of the game. As a result, the NBA created rules against flopping to encourage offensive players to take risks.
Final Thoughts
Whether you’re familiar with the NBA rules or just starting out, there are a lot of things you need to know about illegal defenses to understand the game. The rules against illegal defenses heavily influence the offensive and defensive balance of basketball — and in many ways, they’re significant in shaping how the game itself is played. I hope that this article helped you understand everything you need to know about illegal defenses in the NBA.