Solving Miami’s 2-3 zone defense

The Boston Celtics have been an individual-based offense. Four main scorers all take their turn to go at their opponents, doing more to pre-determine who will create and which hot hand to ride than the read-and-react, flow-based offense Brad Stevens installed early in his coaching tenure. The approach, when combined with as much talent as the Celtics have, is effective enough to hurt most man-to-man defenses.

It struggles against zones.

The Miami Heat have hit all the right buttons against the Celtics through two games, shifting to a zone in long stretches over the second half of each contest. If the Celtics are to solve it, they’ll need to share the ball and create movement of their players, not just stand around and watch their All-Star-caliber talent make hero plays in big moments.

From a theoretical standpoint, the Celtics play four guards/wings and one big at a time. Remove the big and think more about the zone being where you place the other four. If a the floor is cut down the middle, there’s a left side and a right side of the zone. If the Celtics keep two scorers on each at all times, the zone doesn’t really have to morph into something its not. Defenders stay where they want to, and breakdowns rarely occur.

That’s why Stevens spent so much emphasis talking about cutters and moving without the ball. If Boston is stationary, they’re easy to guard. They need random movements, unpredictability, and to overload one side of the floor.

Think about this Marcus Smart cut from Game 2: he sneaks out of one corner along the baseline and to the other side of the floor, throwing off the balance of the zone:

In order for these cutters to matter, Boston has to get past the aggressive top-line of the zone. Erik Spoelstra inverts his looks by putting longer defenders up top and hiding his guards on the corners and back-line of the 2-3. It’s effective at swallowing up driving and passing lanes, particularly on smaller guys like Kemba Walker.

For Miami, it makes a ton of sense to load up the front line of their zone with length and size. They’re armed with three strong wing defenders in Jimmy Butler, Jae Crowder, and Andre Iguodala. In his Game 2 post-game presser, Spoelstra said, “I know everybody wants to talk about a scheme but for us it’s disposition, effort, making multiple plays and multiple efforts.” That veteran trio embodies everything of that Heat culture.

To counter, the Celtics need to get the ball to the high post. They’re at their best when they punch to the heart of the defense. Once there, the overloads matter: if the middle man guards the high post, there are two defenders on each side of him. Overloading one side creates an advantage for Boston that the Heat cannot match.

Okay, that sounds great, but how do you get the ball to the high post? There are, in the simplest form, two ways. You pass it to someone standing there, or you dribble it there, most likely off a ball screen.

The Celts have used a mixture of both thus far. In the clip above where Smart gets a layup, Kemba was able to come off a ball screen from Daniel Theis and have daylight in the middle-third of the floor. That brought Kelly Olynyk away from the rim to challenge his well-respected pull-up, which got Smart open for the dump-down.

In the second-half of Game 2, Miami was a little more cognizant of the high ball screens against the zone (due in part to the monotony of Boston setting them every trip). Instead of letting Boston get penetration to that middle third, they would encourage kickouts to the corners and dare the Celtics to become a jump shooting team.

Watch Duncan Robinson in the clip below. He is so high into the driving lane that Kemba has no choice when using the ball screen but to pass it:

Without dribble penetration there, the Celtics need to fill the high post with a facilitator that can get others open quickly. When the ball goes to the weak area of the zone, it’s on the guy in the middle to be decisive and capitalize on the advantage while its created.

When put in the middle, Smart failed with his quickness and decisiveness. What’s worse is that the Heat simply wouldn’t guard him there. Bam Adebayo, chilling in the middle of the zone, practically dared Smart to shoot the 15-foot jumper. While he didn’t take the bait, Miami’s defense didn’t contort enough to get someone else open. Smart just stood there and played a game of hot potato for 24 seconds while the Heat chased Boston’s shooters off the 3-point line:

Yes, Jaylen got fouled on the play, but my takeaway was that Smart may not be the man to put in the middle here. If the Celtics are to dismantle the zone from the middle out, they’ll need a strong scoring threat who is respected from the free throw line. Even if this isn’t the desired shot location, somebody a little more capable of attacking the middle and finishing at the rim when the Heat sag off is crucial.

The Celtics have used one simple cutter-based play to create an overload. They bring two cutters through to the corners, hoping to create a corner overload that distorts the zone and gets them an open look. It’s a fairly common zone offense principle.

Miami has come prepared. They have two different bumps around it, both of which consist of not guarding the high-post flash and passing off bigs to the top two guys in the zone rather than the middle man coming up:

At this point, it comes down to this for Boston. They need to either punish Miami for not guarding the middle, or put someone there that forces them to guard it, then creating open looks elsewhere. After Game 2, Stevens said, ““It’s a hard zone to play against. We did play well against it in Game 1. We played with way better pace than we did tonight. So we’ll go back and look at it, figure out if it was a technical thing or a pace thing or an execution thing or just not-as-focused-on-the-important-stuff thing.” Stevens may not need to look anywhere other than his past playbooks for inspiration to dice the zone.

During Stevens’ time at Butler, he routinely coached teams that shredded 2-3 zones and would take advantage of the high post, low post, and anywhere in-between:

Some of these may work better than others against an NBA zone, but Stevens clearly has no shortage of tricks up his sleeve. It’s just about finding the ones that work best against Miami’s odd front.

There’s a quick turnaround from one game to the next within the bubble, so large overhauls and new plays aren’t incredibly effective without a ton of practice time. What Stevens needs to preach as much as X’s and O’s adjustments is trusting each person on the floor. Zones are simple in what they encourage: jump shots. The Celtics can be more disciplined with which ones they take, but they still have to be fortunate with which ones they make.

Keep your eyes on the zone offense in Game 3. I’d expect something to change.