Zone defense carries a bit of a stigma in the NBA.
Playing zone can seem like an admission that a team’s man-to-man defense isn’t up to par, or that a team needs to save some energy. At best, it’s a defense reserved for high school and college.
But more and more NBA teams have started incorporating elements of zone on the defensive end of the floor, and the Clippers finally joined the party this season. According to Doc Rivers, it’s something he’s been wanting to do for some time.
"Every summer, I do the same thing," Rivers said. "I go to Winter Park and spend time with Tom Klusman. He’s guy in Orlando that has only run zone for 30 years. He’s never run man. He laughs every year because it’s like ‘you’re never gonna do it.’ We put it in last year, we just never ran it."
This year was a different story. The Clippers projected to be a hellacious defensive team with 2-time Defensive Player of the Year Kawhi Leonard, ace perimeter defender Paul George, and overwhelming length up and down the roster. Rivers thought it was obvious that this team could construct a productive zone with its defensive talent. He even consulted multiple college coaches for tips.
"I just called Rex [Kalamian] this summer and said, 'We have a switchable basketball team for the first time in my career. And we're gonna zone. We're gonna zone a lot.' And we've been very effective," Rivers said.
Kalamian, the assistant coach responsible for the team's defense, didn't believe the Clippers would actually play zone until they started doing it. Rivers says the players still don't think the team will stick with this change, and his former assistant and good friend Tom Thibodeau is "disappointed" in him.
It hasn't been a dramatic overhaul. Per Synergy stats, the Clippers have played zone on 4.6% of their defensive possessions this season, or 173 possessions total. That is the 13th-highest frequency in the league; as a point of reference, the top 10 teams all play zone at least 10% of the time.
When the Clippers play zone, the head coach's prediction has proven correct: the team's defense is awesome. According to Synergy, they allow only 0.78 points per possession, the second-best mark in the league, on 36.8% shooting. The Clippers' man defense yields 0.929 points per possession.
The key for L.A. is playing a zone that essentially functions like a switching defense. It keeps the players active because it morphs back and forth with a man defense, to the point where Rivers refers to it as a "flex zone".
Most of the Clippers played zone in high school and/or college, but an NBA zone requires different principles. NBA teams have multiple players who can handle an initiate an offense, so defenses can't overload. Defenders have to play up higher, too, because NBA players have the threat of a pull-up jumper if the defender sags too far back.
The Clippers' length is a helpful counter to some of the challenges of a zone, though offensive rebounding has occasionally been a problem, as it was in a loss to the Thunder last month. The team has spent enough time playing zone that they can start to figure out when they're making mistakes. The Clippers didn't put anything new into their two full practices last week, but they did focus on cleaning up some of the issues they've had on defense.
Although the Clippers leaned on zone when they had injuries limiting their personnel, the purpose isn't for the team to save its legs on defense – they want to disrupt the other team's flow. Rivers says he specifically likes to use zone out of timeouts to take their opponent out of a set play.
"It just messes up rhythm," Patrick Beverley said. "NBA teams, you don't find yourself working on your zone offense that much because you don't practice a lot. Throwing a zone in there, it kind of throws everything off a little bit."
There are certain opponents where it doesn't seem to make sense to play zone. Rivers noted before the team played the Lakers that their size could make zoning a challenge, but their switching stifled the Lakers' offense in the Christmas Day matchup anyway.
Nikola Jokic is the type of big who would appear to preclude zone as well when the Clippers face the Nuggets Sunday, but like the team said, the point of zone is sometimes to be unpredictable. That might be why more NBA teams continue to sprinkle a bit of what has been referred to as a gimmick defense into their defensive diet.
"I think each year, you can see it. More teams are starting to do it more and more," Rivers said. "And listen, we’re scoring 130 every night against man, so we’ve got to try something."