How the Heat turned their defense into a house of horrors

The Miami Heat really don't want you to score. So far this season, no team has made doing so a more enervating task for opponents.

The Heat were already a top-10 defense last year behind stalwarts Jimmy Butler and Bam Adebayo, but adding Kyle Lowry and P.J. Tucker to the mix has transformed them into an altogether different beast. They no longer need to rely on gimmicks like zone or hyper-aggressive blitzes to protect weaker defenders in their rotation. They're allowing just 97.9 points per 100 possessions. No team's been that stingy over a full season in 10 years.

Miami is stocked with great individual defenders, but the team's success so far is the product of how it defends as a unit: cooperative, communicative, on a string. Players cover for each other, trade assignments on the fly, and almost never botch their help rotations. It often feels like the five defenders on the floor are tendrils of a single organism, all of them guided by the same brain:

The Heat were already a switch-heavy team, but Tucker and Lowry make them even switchier. And while switching is often not the panacea some make it out to be, it's a tough coverage to crack in Miami's case because there's rarely an advantage to leverage on either end of those switches. A guard trying to go at the fleet-footed Adebayo usually isn't going to work out well for the offense. A big man trying to post up brick houses like Butler or Tucker or even the 6-foot Lowry is equally unlikely to produce a favorable result.

Coupled with Heat guards' and wings' aptitude for tagging and recovering when they opt not to switch, or when opponents counter by slipping screens, that causes a lot of bread-and-butter pick-and-roll possessions to completely stall out:

Switching defenses tend to struggle on their own glass because of how often they wind up with size mismatches under the basket, but the Heat lead the league in defensive rebound rate at 78.9%.

Miami's rotation does have two defensive minuses in Duncan Robinson and Tyler Herro. While those guys struggle on-ball due to a relative lack of lateral speed and strength (and, in Herro's case, length), both of them have become solid team defenders who can at least be relied upon to be in the right spots at the right times. They're always going to be hiding on the worst opposing offensive players anyway, and when they get hunted in screening actions, Miami has a strong enough infrastructure to insulate them. The Heat will send double teams or just show extra strong-side bodies, trusting themselves to zone up and rotate behind the help to erase whatever initial advantage they concede.

Consider this possession against the Brooklyn Nets, in which James Harden looked to attack Robinson. The Heat ceded the switch without any resistance (which is something they could probably stand to do less often), but then immediately brought Butler over to double and force the ball out of Harden's hands. The Nets then put Miami in rotation, but all their windows slammed shut pretty quickly:

Lowry started that possession by overloading the strong side to protect against a Harden drive, then flowed from bumping Bruce Brown's cut in the middle to closing out on Blake Griffin in the far corner while barely breaking stride. Griffin immediately looked for what he assumed would be an available dump-off pass to Brown, but Robinson had perfectly synchronized his rotation with Lowry's and had already put himself between Brown and the ball. Griffin thought for a moment about trying to back down Lowry, then thought better of it and kicked back out to Harris for a contested triple.

When it comes to rotating, if you're not early, you're late. Joe Harris definitely should’ve taken this shot, but the possession still looked promising for the Nets after he swung the ball to Griffin. The Heat were able to snuff it out because Lowry and Robinson started rotating to their next assignments before Tucker even made a move to close out on Harris from the corner:

The Heat give up a boatload of threes - no team surrenders a higher rate of opponent shots from beyond the arc - but they also have the league's lowest opponent rim frequency. That's all very much by design, because one of Miami's few defensive weak spots is rim protection.

As good as Adebayo is, he's a bit undersized for a center, and he isn't exactly flanked by secondary rim-protectors - the 6-foot-5 Tucker is the team's primary power forward and sometimes even its backup center. Opponents shoot 66.4% in the restricted area against the Heat, which is the eighth-worst mark in the league. So they rely on keeping the ball as far away from the basket as they can.

Switching is a big part of that; it helps them flatten opponents out and prevent north-south action. But the Heat are also aggressive about helping in the middle of the floor, whether that means wing defenders pulling over to the nail or corner defenders pinching or digging on drives. And that, as much as anything, is where Lowry has really made his defensive impact.

On defense, Lowry is a guard in name only; at this stage, he defends more like a pint-sized power forward. Point-of-attack containment is no longer his forte, but few players of any stature are better at blowing up drives or short rolls as a helper from the weak side.

His timing is what makes him so disruptive. He excels at planting himself in the lane at exactly the right moment, forcing unsuspecting drivers to either bowl him over for a charge or pick up their dribble and frantically look for an escape hatch:

Miami's opponents get to the rim 5.4% less frequently with Lowry on the floor, an 87th-percentile differential, per Cleaning the Glass.

The Heat are getting extremely lucky with defensive shooting variance, which is why their scheme has worked like gangbusters. Their opponents are shooting just 31% on threes and 16% on long twos, and that will regress to the mean in a major way. Forcing so many jump shots won't always look like such a foolproof approach. Butler won't always be able to make this kind of reckless, no-hope gamble (an increasingly bad habit of his) and get off scot-free:

But while some measure of regression is coming, it's noteworthy that Miami's opponents rarely seem to establish a good offensive flow. A lot of the threes the Heat surrender are well-contested, last-resort shots that come after Miami shuts down actions one, two, three, and four.

It also helps that the Heat take away a lot of low-hanging fruit. They don't allow second-chance points, and their transition defense is smothering. Go watch their game against the Hornets from last week and try to count the number of times LaMelo Ball wound up as if he was going to hurl a live-dribble hit-ahead pass, only to keep the ball because all his down-court options were covered. Charlotte has shredded teams on the break all season, but the Hornets got nothing against Miami in the open floor.

That's particularly impressive considering the Heat don't even punt the offensive glass, which is typically seen as a prerequisite for getting matched up in transition. They're the fourth-best offensive rebounding team in the league. The ability to crash hard and still bust it back and get matched up quickly when they come up empty is a killer combination.

There's a long way to go, and we'll have to see if the Heat can sustain this effort and energy level over the course of the season and into the playoffs. Their age may well catch up to them at some point. Their opponents will inevitably shoot better.

For now, though, no team is defending as well as Miami.