It’s midway through the fourth quarter of a tie game in Boston, and Jayson Tatum is smelling blood. As he accelerates down the right wing, he spots a dream scenario for any elite wing scorer in 2020: a scrambled Houston Rockets defense running to match up, leaving nobody on the second line of defense. The proverbial “wall” every coach begs their team to build to stop great players in the open floor was nowhere to be found.

What happened next was a flashpoint moment in NBA tactical history. It explains why the Rockets’ small-ball approach is so successful, why Robert Covington and P.J. Tucker deserve far more appreciation than they’ll ever get, and how the unique demands of the modern game have changed the way teams successfully protect the rim.

As Tatum advanced to the three-point line, he hit Covington with a hard righty dribble. Covington read the move and slid to meet it, bumping Tatum at full speed while using his strong chest and powerful hips to stay on his feet. Against many defenders, Tatum explodes through the bump and scores. This time, he spun left, hoping that counter move would shed Covington for good as it so often does to other defenders.

It did, sorta. But something else happened during the failure of the initial move: Tucker had enough time to rotate down and meet Tatum on the other side. Using his wide chest, Tucker did what much taller shot-blockers do to stay vertical when contesting shots at the basket. He squared up and dared Tatum to go through him.

Tatum did, but he had another problem now. In the split second it took for him to gather any strength he could to power through Tucker’s verticality, Covington recovered and swiped at the now-exposed ball. We’ll never know if Tatum could have finished through Tucker because he didn’t have control of the ball long enough to do it.

This sequence had everything great rim protection requires. It featured great positioning, rock-solid sturdiness, and straight arms to avoid a foul. The Rockets stayed balanced to negate Tatum’s explosiveness and even got an actual block for their troubles. These are the qualities that make giants like Rudy Gobert so good at thwarting the most efficient shots in basketball.

Tucker and Covington may be two people, and specifically two people that are not considered rim protectors because they stand 6’5 and 6’7, respectively. But if they do everything rim protectors do anyway, what’s the difference? That’s the Rockets’ bet, and it’s been game-changing.

Turns out P.J. Tuckington is an intimidating presence at the hoop. Houston allows teams to shoot just 59.1 percent at the basket with that combination in the game, according to Cleaning the Glass. That’s on par with the Lakers’ mark when Anthony Davis and JaVale McGee share the floor, two percentage points lower than L.A. allows with Davis on the court with whoever else, 2.5 percentage points better than the 76ers surrender with Joel Embiid on the court, nearly three percentage points better than Jazz opponents shoot with Gobert on the floor, close to five percentage points better than the Rockets allow from that zone with Clint Capela and Tucker sharing the court, and 5.3 percent more than they did with just Capela out there.

Think about that for a second. Lineups anchored by a 6’5 pancake-loving thicc dude and a 6’7 wing player on his third team in 14 months aren’t just better at altering shots at the rim than lineups anchored by the only tall guy the Rockets previously had. They’re also better at altering shots at the basket than lineups built around three of the NBA’s best rim protectors.

How is this possible? A few related factors:

“They’ve got a lot of middle linebackers on that team”

Those were Steve Kerr’s words during last year’s Warriors-Rockets playoff series, and they’ve since been repeated by Boston coach Brad Stevens. The analogy references the difficulty of posting Houston’s smaller players up despite having a height advantage. Middle linebackers aren’t usually the tallest football players, but they have the lowest center of gravity while also retaining more mobility than defensive lineman. Or so the theory goes.

With Tucker and Covington specifically, the same principle also applies when defending drives to the basket. Their lateral quickness is solid, but that’s not why they are able to stop so many different kinds of drives before they get to the rim. The reason they do is they have chests and hips of steel.

Any driver hoping to surge to the basket in this spread-out league must possess the ability to power through contact. Try to dance around defenders, and they’ll just close off the angle using fewer steps than a driver does. The difference between a successful drive and an unsuccessful one comes in the split second when the offensive players’ shoulders meet the defenders’ staked-out position. If the driver can get their shoulders past the defender, they will probably score and/or draw a foul. But if the defender can absorb that body blow and maintain that space while moving their feet and keeping their arms level, they have the advantage.

That’s way easier said than done, especially if the offensive player is supremely quick, broad-shouldered, and/or given a running start. Yet this is exactly the moment that Covington and Tucker dominate. Their chests absorb body blows without surrendering leverage, and their hips allow them to slide their feet effectively and still maintain their positioning.

Watch Mike Conley try to go past Tucker on this drive.

Or Kemba Walker.

Or Gordon Hayward and Daniel Theis.

Covington’s chest isn’t as conspicuously wide as Tucker’s, but it’s just as effective. Just ask Jaylen Brown.

Or Donovan Mitchell.

Or some bum named LeBron James.

We wouldn’t necessarily call this rim protection, but it functions the same way. To be successful at staying vertical and altering shots at the basket, one needs a strong enough chest to absorb a blow without losing balance and lowering your hands. Great perimeter defense in the anti-handcheck era is also about having a strong enough chest to absorb a blow without losing balance. Covington and Tucker, then, are essentially maintaining verticality, except further out on the floor.

You don’t need to be tall if your opponent never jumps his highest

Houston runs a switch-everything scheme, but it’s misleading to suggest they don’t want to make defensive rotations. If the game really devolved into a series of one-on-one contests, they’d probably lose because they have weak defenders like James Harden and Russell Westbrook. The opponent’s strategy would be simple: spread the Rockets out, make either of those players defend in space, and profit.

That hasn’t happened much in practice, and it’s because Tucker and (especially) Covington also eat up space as help defenders. Both are adept at swarming to the ball, and both do an excellent job of helping the helper so the next pass isn’t open. They ensure the weak Rockets defenders aren’t exposed in space.

The speed and recognition on this sequence are remarkable. Tucker quickly switches off his man to stop Boston from using Harden’s man to screen, and Covington is already rotating down to cover for Tucker when Brown slipped the screen to sprint to the wing.

How does this make the Rockets tough to score against at the hoop when both share the floor? Consider the build of a prototypical rim protector: tall, strong, long, and able to keep those arms straight while in mid-air. Those traits seem essential because we think of big men as the type of players who can meet players at the apex of their jump. If P.J. Tuckington had to meet drivers at the apex of their jump, “he” will lose because “he” is not tall.

But that’s only a problem if they actually reach the apex of their jump. By wedging their way into tight help positions and staying there due to the power of their lower body, Tucker and Covington ensure that anyone who tries to finish over them can’t in practice because they don’t have enough space to leap their highest. Gobert is much taller than both, but what does it matter if he doesn’t have enough space to take off?

That’s how Tucker and Covington play much taller than their height even when their man doesn’t have the ball.

This wall moves

Two years ago, I introduced the concept of a “portable” rim protector, using Anthony Davis as the idealized version. The idea was simple: what if you could take a stationary barrier and move it to wherever you needed to move it? As I wrote then:

Great rim protection builds a barrier around one valuable piece of real estate. That’s useful, to a point. The Great Wall of China sure did well to keep Mongolian tribes away from the Ming dynasty. But in today’s NBA, where teams are proficient at all sorts of aerial attacks from different spots on the court, it’s far more valuable to have a portable Great Wall to drop in wherever necessary at any given time.

Davis has length and lateral quickness that Tucker and Covington don’t, but they serve a similar function in Houston’s switch-everything scheme. They are each portable brick walls — or at least hand-held shields the Rockets can deploy anywhere. They allow the Rockets to string together crucial defensive possessions like the clincher in Boston last Saturday, when they collectively prevented Tatum, Hayward, and Brown from getting to the basket thanks to a series of switches. Tucker was the brick wall that planted himself in front of Tatum 30 feet from the hoop, while Covington was the brick wall that stopped Brown from getting downhill

After all, you can’t score at the rim if you never get there.

Covington and Tucker are a special tandem

Defending the rim this way simply doesn’t work unless both of them are on the floor. They already work beautifully together, funneling their own men into the waiting jaws of the other lurking on the backside.

Tucker is the better clamp defender of the two, while Covington is more adept at flying in to generate the crucial steals or blocks. He’s averaging a whopping 2.5 swats per game since arriving in Houston, which would be second in the entire league if maintained over enough minutes. They combine brilliantly to produce crucial turnovers like this.

But they can also flip roles if the situation calls for it.

They have incredibly unique skill sets that are nearly impossible to find elsewhere in the league. What Harden and Russell Westbrook are to one-on-one offense, Covington and Tucker are to switch-heavy defense. They are as valuable as Houston’s offensive stars and should be treated league-wide as such.

By bringing them together, the Rockets have hacked a modern basketball cliche. You need rim protection to succeed, but you don’t necessarily need rim protectors.