Are the Miami Heat the future of NBA defense?

In his 2014 novel Basketball Analytics: Spatial Tracking, Stephen Shea identified rim protection as the most important variable contributing to a team’s defensive rating.

Looking at the crème de la crème defensively in 2023, Shea’s insight seems to still apply today:

Screenshot from NBA.com on January 29, 2023

The teams ranked one through four on this list all have multiple giant Guardians. The Cleveland Cavaliers with Jarrett Allen and Evan Mobley. The Memphis Grizzlies with Jaren Jackson Jr. and Steven Adams. The Milwaukee Bucks with Brook Lopez and Giannis Antetokounmpo. The Boston Celtics with Robert Williams III and Al Horford. And the Miami Heat with Bam Adebayo and…wait, what other big bodies has the heat patrolling the paint?

Interesting.

Another observation Shea made during his research was that blocks are a solid way of measuring a team’s rim protection skills.

Well, Miami ranks last in this category — not just among the top 5 teams, but among all teams in the NBA — averaging just 2.9 blocks per 100 possessions. Meanwhile, three of the other four teams mentioned sit in the top eight.

So what gives? How is this defense so good?

I’ve been wondering that for a while too, so I decided to take a look under the hood. What I found was not only the answer to my question, but perhaps the blueprint for how teams can build their own elite NBA defenses without a surplus of rim protectors.

First, let’s explain why protecting the rim is so important.

According to Cleaning the Glass, the league average for all mid-range shots is 43 percent (0.86 points per possession). The league average for all three-point shots is 36.4 percent (1.09 points per possession). The league average for all shots on the edge is 66.5 percent (1.33 points per possession). So by protecting the edge, you are protecting the most efficient part of the floor.

Now that that’s out of the way, the next question arises: how do you protect the paint?

Remember that scene from The Usual Suspects where Kevin Spacey says, “The biggest trick the devil played was convincing the world he didn’t exist?”

The same goes for great rim protectors/rim protection teams. They don’t let you miss a lot of shots around the rim. They fool you into thinking that this area is not an option at all. They convince you that there is no shot on the edge.

For example, the Bucks allow the fourth-lowest percentage of shots around the rim with Lopez and Antetokounmpo (according to Cleaning the Glass). They do this by keeping the twin towers close to the paint to discourage potential invaders from entering that area altogether. You can’t shoot around the rim if you can’t even get close to it (unless you’re in Looney Tune Land).

Our friends in South Beach have the third-lowest fringing frequency of opponents, though they don’t tout the statuesque deterrents that the Bucks have.

How do you ask? It’s time to meet the two faces of Heat’s defense.

The first face is the base cover of the Heat. I like to call it the hyena heat. As the name suggests, they’re wild when Miami is in this mode. They catch/cover, make hard transitions, gape a pass, dig/stunt the ball, face the post and aggressively deny the ball to cutters. The Hyena Heat have two main priorities: forcing turnovers (first in percentage of opponents turnovers) and keeping the ball in front of them (aka point-of-attack defence).

It’s difficult to fire off shots on the edge when the defense has two big bouncers waiting for you in the paint. But it’s also difficult to shoot from the edge if you can’t get into three-point arc or even keep possession.

And just as the size of Lopez and Antetokounmpo is critical to Milwaukee’s success, Adebayo’s versatility is paramount to the integrity of the Hyena Heat’s armored barrier.

It’s not breaking news or anything, but Adebayo is one of the few players in the league who can literally defend all five positions. That means Offensive can’t try to chase him from dribbling on the Switch. Not only can he hold his own against players one through five, but it could be argued that he’s the least discriminatory defender in the league. It doesn’t matter what your anatomical structure entails. Upon entering Adebayo’s world, you will receive a heaping bullet Shutdown.

With Adebayo on the five and their barrage of wild border guards and forwards (Greetings Haywood Highsmith) Hyena Heat Fortress leaves few weak spots for enemy teams to exploit.

In many ways, this version of the Heat is similar to the Toronto Raptors, who also blitz and pressure opponents to get them to flip the ball.

Wait, the raptors? Hasn’t their defense been exposed this season? How are the Heat like them?

Well, well, my friend. Read my last sentence again. I said “this version” of the Heat. As you remember from before, Miami’s defense wears two masks.

The reason Hyena Heat is thriving while the Raptors are desperate for answers is because Miami has another playing field to go to when teams hit their fastball. Or, as former coach Jeff Van Gundy put it in The Lowe Post, they have an “alternate defense.”

That alternate defense that Gundy mentioned is Heat’s now-patented zone defense. I say patented because this year they have become industry leaders in this field. According to InStat, Miami has executed 926 zone possessions this season. The zone’s second-biggest supporters are the Portland Trail Blazers, who managed it just 365 times in 2022-23.

For most of NBA history (outside the part where it was illegal), the zone has typically served two functions:

1. As the basketball equivalent of a flashbang, the zone was intended to temporarily disorient an offense so a team could get back in play/put them out of range.
2. The zone also (for a time) helps weaker defensive teams cover their lack of manpower by giving attacks a ground configuration they’re not normally used to.

The big problem with zone defense is that once an offense has figured it out (or “zone cracked”), many coaches find it more harmful than helpful. Also, many coaches worry that it will teach bad habits, since it theoretically requires less ground cover from each individual defender than standard man-to-man defense.

I say most coaches because Miami’s Erik Spoelstra doesn’t subscribe to that school of thought. He will continue to switch back and forth between the Zone and Hyena Heat even as teams appear to have resolved the former.

Spoelstra understands that just because a team has beaten the zone in one possession doesn’t mean it will do so for every possession for the rest of the game.

People forget that players are making the decisions they make on the pitch in real time and at breakneck speed. In the heat of battle, they don’t have the benefit of a broadcast camera perspective to spot the zone, a slow motion feature to spot the zone’s weak point, or a rewind button to see where they screwed up should they do fail.

They need to be able to spot the zone from the ground, figure out how to attack and execute accordingly. It’s an incredibly mentally draining endeavor, especially when the team keeps forcing you to do it.

Combine that with the simultaneous concern that Miami could return to their more aggressive base coverage, and it’s no wonder the Heat have been able to execute them so frequently and with such success.

As for the deleterious tendencies that players might develop if they zone too much, Miami’s famous “heat culture” pretty much negates this potential compromise. The grueling regimen of fitness that this organization demands of its players has probably banished any laziness from their very nature. I mean just look at how active and alert they look in these zone possessions:

As for the zone’s rim protection angle, Miami usually hovers between 2-3 and 1-1-3. Regardless of orientation, both iterations of the zone allow three bodies to be stored inside. Even if these bodies aren’t as menacing as the Lopez and Antetokounmpo, three bodies in the color still present a daunting task for drivers considering an escapade toward the rim.

The ingredients of Miami’s top five defenses consisted of a mode focused on building a shell around the perimeter and forcing turnovers, and another that tested the limits of the opponent’s allostatic load and flooded the paint with bodies .

Well, it’s worth noting that not every team can pull this off without problems. You still need a moveable fiver, an abundance of turnover-inducing point-of-attack defenders, a company-wide buy-in, and a coach willing to trust the process more than the results.

But still, watching what Miami has done should give other teams hope that they can put up great defenses too, even if they don’t have a bunch of huge shot blockers that make life easier in the middle.