Zone, Culture and the NBA Finals
By: Kevin Wang
After a dynastic run of three titles in five seasons, the juggernaut Golden State Warriors had popularized switch defense, where defenders, after hitting picks, would essentially swap assignments with whomever was guarding the screener. Off-ball actions for shooters would be negated. Pick-and-rolls would devolve into aimless post-ups and isolations late in the clock disguised as mismatches. The basic counter to this is to bait switches until the opponent’s worst defender on the floor is matched up against your ideal scorer. “Whoever Offense” was the phrase Chris Smoove coined to describe this phenomenon and it has remained a staple in many of today’s late game offenses, especially in the postseason.
So, when the Celtics, fresh off of a grueling bucket-famine of a Game 7 against the Raptors, advanced to the Eastern Conference Finals, the media was optimistic regarding how they matched up against the Heat. Boston had just defeated a team whose third most exploitable defender in the rotation was arguably Marc Gasol, a former Defensive Player of the Year (over 2013 LeBron, I might add). After a series where they faced every defensive scheme imaginable— man-to-man, 2–3 zone, 1–2–2 zone, full court press, heavy blitzing, box-and-one, and even triangle-and-two, they would soon face a Miami Heat team with fewer off-the-dribble shot creators, and more exploitable individual defenders.
The Heat had previously eliminated the Milwaukee Bucks in an impressive five games, but some worries defensively were still justifiably present. After all, they had ranked only 12th in Defensive Rating (DRTG) between February 9 (Crowder and Iguodala’s debuts) and August 14 (their regular season finale), giving up 110.9 points per 100 possessions. While Milwaukee scored 111.9 points per 100 possessions in the regular season, good for an impressive 8th place, there was understandable skepticism pertaining to how intricate their offense was in a playoff scenario too. After all, that offensive rating (ORTG) showed how they fared on average against all 29 other teams in the league. In some instances, presenting regular season ORTG to foreshadow postseason success can be false extrapolation. Facing one opponent up to seven consecutive games means endless scouting, which results in offenses being stripped layer-to-layer. As defensive schemes tailor-made to neutralize your first, second, and even third options are carefully plotted, plays inevitably break down, and counters become increasingly significant to scoring success.
As seen in last season’s elimination against the eventual champion Raptors, the Bucks once again had insufficient offensive improvisation and versatility this year. Aside from Middleton, Milwaukee lacked the necessary pull-up threats (and shooting, in general) to cripple Miami’s drop coverage. Bam, with the help of a trio of jacked wings in Butler, Crowder, and Iguodala, trapped Giannis and walled off his drives more effectively than any team had done all season. And with Budenholzer reluctant to make major adjustments, the Bucks broke the moment they were bent. Miami had flummoxed the league’s MVP and top seed, but the absence of legitimate dynamism from Milwaukee’s offense still left the door open for concern. Yes, they had successfully studied to the test to earn an A+ and stifled a borderline elite yet rigid offense in the process, but an even more difficult exam was awaiting them.
Entering this series, the Celtics possessed two players who excelled in areas that Miami struggled defending. Jayson Tatum, a lengthy 6’8″ wing with an improved handle, shot 41.1% on 246 unassisted 3-point attempts (via Kirk Goldsberry). Kemba Walker’s twitchy, quick-change-of-pace style fit the prototypical point guard that troubled laterally challenged guards. Both were essentially designed in a basketball laboratory to kill drops and immobile white guys. Through 4 games however, despite the matchups and talent advantages favoring Boston, Miami has a commanding 3–1 lead in part thanks to an inverted zone defense that has negated their mismatch-hunting and made them see ghosts. Together, Tatum and Walker have combined for 37 assists and 28 turnovers, while hitting only 22 of 68 3-point shots. The Celtics struggles against zone defenses in the postseason continued, scoring just 0.833 points per possession (PPP), and their opponents have noticed this downward trend, as Boston has faced an incredible 251 zone possessions (via Synergy).
Next are the Clippers with…50 total possessions. If you’re only interested in remaining teams, the Lakers have dealt with just 30.
In seven games against Toronto, arguably the best defense in the league, Boston scored 91 points against 117 zone possessions (0.778 PPP). Through just four games, Miami has already surpassed that number, and despite playing several more exploitable defenders, have still limited Boston to 109 points in 121 zone possessions (0.901 PPP). Contrary to conventional practice, Spoelstra positions his wings up top and his guards in the backline, with the lone big in the middle. This inverted zone has created new challenges that the Celtics had not previously seen against the Raptors.
As Jackson Frank had previously written, Tatum began showcasing steady improvement as a playmaker towards the end of the season’s pre-pandemic portion. Against Toronto, he displayed advanced reads by weaponizing his pull-up gravity to create passing lanes and dot high-velocity skip passes crosscourt past rotating defenders, thinking one step ahead of them.
Against the Heat, however, certain reads have been neutralized. With two of Butler, Iguodala, Crowder, and even Jones Jr. up top for the majority of zone possessions, not only are longer arms threatening to intercept these passes, but they are also shutting down initial drives from Tatum and Walker. Furthermore, despite being limited lateral athletes, Miami’s guards, positioned near both corners, have excelled at stopping penetration whenever the wing is beaten at the point of attack, before recovering to the corner and funneling their current assignment to the big. Adebayo has also been otherworldly as a security blanket. He is by far the quickest big laterally Boston has faced up to this point, as Horford, Embiid, Gasol, and Ibaka were all much more comfortable sitting in drop coverage.
Here, Theis tries to overload the zone by screening for the ball handler up top before rolling. Robinson shows high to take away Walker’s pull-up 3 and then immediately sprints back to Brown after correctly anticipating the next pass. From there, he runs Brown off the three point line, funneling his drive baseline to the help in Bam, who’s positioned himself to contest both Brown’s shot and Theis’s layup barring a potential drop down pass.
One wrinkle that Stevens deployed to try and take advantage of the guards showing so high on the point of attack was setting flare screens to free up the corner shooter — often Brown spotting up or Walker relocating after bringing up the ball.
Against the Raptors defensive alignment here, Tatum likely lasers the rock straight to Kemba in both instances for corner 3s. Such passes aren’t as easy to make against the Heat’s zone, however. No matter how stout defensively Lowry and VanVleet were, both still stood at merely 6’0″. With Iguodala, Butler, Crowder, and Jones Jr. all between 6’6″ and 6’7″, those same reads are far more difficult to execute, as the same passes must be thrown higher to avoid being snatched by the team that currently leads the league in average playoff deflections (Miami‘s at 14.7 while Toronto was 9th at 11.4). The extra half seconds of indecision that Jimmy and Jae force are just enough for Dragic and Robinson to fight through. And even if Tatum successfully launched both passes through tight avenues to Walker before the guards (who’re 6’3″ and 6’7″, respectively) navigated the picks, shooting a jumper with Bam sprinting to close out is a far different experience than say, Marc Gasol trying to make it in time.
Spoelstra sometimes even mimics Nurse’s backcourt press before settling into their 2–3, which, given how disciplined the Heat have been at avoiding silly gambles for steals, burns 3–4 extra seconds off the shot clock before the Celtics begin initiating their offense.
All season long, the Celtics flourished offensively through collaborative hero ball that featured their 4.5 perimeter creators (Brown is mainly a play finisher than a play initiator) bending defenses and making the correct reads. Despite Boston still scoring at a high level this series, producing a 113.4 ORTG, the zone has put their talented perimeter players in uncomfortable positions in half court situations. Breaking Miami’s 2–3 requires quick passes and intuitive off-ball manipulation (such as random cuts, constant off-ball screening and movement) that the Celtics simply did not have enough repetitions of in the regular season to properly execute now. This lack of familiarity, combined with the dearth of legitimate catch-and-shoot threats outside of their main creators has Miami forcing Boston to turn it over on 22.6% of their 4th quarter possessions (via nba.com).
The Heat’s final obstacle before the franchise’s first NBA Finals appearance in six years will likely be extended run against Boston’s Walker-Smart-Brown-Hayward-Tatum Costco Death Lineup. Since Hayward’s return, that group has outscored Miami by 14 points in just the 11 minutes they’ve played together. With Stevens likely relying on his five best players in potentially Boston’s final bubble battle, Miami will have to pass one more test before they can focus on the Lakers or Nuggets.
Regardless of how the playoffs finish for Miami, the last few months may be retroactively examined as one of the more impressive mid-season defensive improvements in recent league history. Their defense today is a far cry from the deep drops that hemorrhaged open three-point shots for most of the regular season.
Having gone from customary man-to-man switches against Indiana, to aggressive traps against Milwaukee, and now heavy zone usage versus Boston, Spoelstra has successfully reinvented the Heat’s defense—now ranking 2nd in playoff DRTG among remaining playoff teams and 5th overall at 107.8— amidst a variety of offenses. To effectively execute these schemes on the fly after acquiring 2 new rotation players at the trade deadline only further bolsters his case as the NBA’s best coach.
Now THAT is #HeatCulture.