How Duke Transformed its Defense from a Susceptible Shortcoming to a Special, Stifling Zone
By 2015, Nolan Smith had seen a lot of Duke basketball. He’d been a fan of Jay Williams during the point guard’s early-2000s stint as a Blue Devils star, then played four years in Durham himself, starting on Duke’s 2010 national championship team. That was coach Mike Krzyzewski’s fourth title, which he’d won the same way he’d won the three before it: with his Blue Devils playing the same aggressive, floor-slapping man-to-man defense that they played year-in, year-out. Which is why, as Smith took in a Duke game three years ago while rehabbing from knee surgery in Durham, he was taken aback to see the Blue Devils get back on defense and... spread out, stake their spots and line up in a zone.
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“I was shocked,” said Smith, who is now a special assistant on Krzyzewki’s coaching staff. “I was like, ‘What? Zone? What Duke team plays zone?’”
Three years later, even as what was once heresy has become effective pragmatism, it can still seem bizarre to see Blue Devils defenders, not up in their opponents’ jerseys but shuffling side to side with their arms out as the ball reverses, like indecisive crabs. But Duke today is not just a team that plays zone; it’s a full-on zone team. According to Synergy Sports, in its last 11 games (beginning with a Feb. 11 win at Georgia Tech), the Blue Devils have played zone on 94.4% of their defensive halfcourt possessions, which, subjectively, actually seems low. But more than just being surprising, that change is one of the primary reasons the No. 2 seed in the Midwest has emerged from the tournament’s opening weekend looking like it could be the best team in the bracket.
Krzyzewski’s 2015 foray into zone—which never reached the stage of full-time adoption, with the defense being used on just six possessions in Duke’s national title win over Wisconsin—was born out of desperation in the predawn hours of all-night coaches’ meeting. After his team had been pick-and-rolled apart in consecutive games against NC State and Miami, Krzyzewski was ready to try just about anything. After two seasons of sporadic use, there were early inklings that we might see a revival, in no small part because this year’s team, like the one in 2014-15, was so dependent on freshmen for whom a quick education in man-to-man intricacies is hard to ace.
The Blue Devils played zone extensively in a preseason exhibition against Bowie State, then employed it effectively for stretches throughout their nonconference schedule. But coaches thought some of its effectiveness may have stemmed from the element of surprise, as opponents primarily prepped to face man-to-man. In the meantime the Blue Devils’ defense as a whole was ineffective and disconnected; by early February, despite being loaded with five-star athletes and NBA prospects, Duke’s adjusted defensive efficiency ranked in the 70s nationally. “The rotations were off,” said freshman guard Gary Trent Jr. “The talk was off.”
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A trip to New York provided the impetus for change. On Feb. 3 Duke played at Madison Square Garden against a St. John’s team that had lost 11 in a row and came away with an 81-77 defeat in which it allowed a dismal 1.19 points per possession—roughly equivalent to what the country’s 300th-ranked defense averaged this season. Krzyzewski called the performance “disgusting,” and the Blue Devils’ next defensive showing was even worse: 1.26 points per possession in an 82-78 loss at North Carolina. Soon Blue Devils practices had a singular focus: “For a week straight,” said sophomore forward Javin DeLaurier, “all we did was defense.”
Afterwards, the defense they played was different. Over those two losses, Duke had played 81.0% of its possessions in man-to-man; its next time out, at Georgia Tech on Feb. 11, it played zone 81.82% of the time, allowing a more respectable 0.99 points per possession. Three days later, at home against Virginia Tech, the commitment and results were both more extreme: zone on 52 of 53 halfcourt defensive possessions, and 0.89 PPP. “It just gradually happened,” said assistant coach Jon Scheyer, who played for Krzyzewski from 2006-10 and has been on his staff since 2013. “It wasn’t a thing where we just talked about it and”—here Scheyer snapped his fingers. “To commit totally to it, it’s a little surprising,” he added. “But it’s been smart and it’s been good for us.
Good might be an understatement. After defensive lapses dogged them for the season’s first three months, the Blue Devils defended so well down the stretch—at one point holding Louisville and Syracuse to season-worst performances in consecutive games—that they ended up with the ACC’s No. 2 defense during league play, behind only No. 1 overall defense Virginia. The same Blue Devils who in early February ranked well outside the country’s top 50 per-possession defenses entered the NCAA tournament ranked in the top 10.
“We have a lot of fun playing it,” said DeLaurier, a 6’10” forward whose floor time increased with the zone emphasis. “We do a better job of talking, which helps bring us together.”
“Your head has to be on a swivel,” said senior guard Grayson Allen. “You have to always be looking out where guys are. So there's no ball watching, no man watching like what can happen when they're playing man-to-man defense.” Which is not to say the zone does not come with its own challenges, namely defensive rebounding, as defending an area rather than an individual can make boxing out more difficult, not to mention the zone’s less natural fostering of aggression. Such challenges are not new to those with prior zone experience, though it’s not clear anyone has experienced playing in one quite like this. “The main difference between this one and other ones I played in,” said Trent, “is my teammates are longer, taller, faster, stronger—one through five. It’s crazy.”
Therein lies the truth strength of Duke’s 2-3 zone setup. When DeLaurier is on the floor, the zone’s back line of he, Wendell Carter Jr. and Marvin Bagley III all stand either 6’10” or 6’11”, with wingspans to match and an athleticism rarely found in such groups. When that same lineup is paired with the 6’5” Allen and 6’6” Trent up top, the overall length can seem downright unfair. (The effect is only lessened slightly when DeLaurier is replaced by 6’3” guard Trevon Duval, which bumps Trent to a wing spot on the back line.) “I was in the Big East for 13 years,” said Rhode Island assistant Tom Moore, a longtime UConn staffer when the Huskies competed in the previous incarnation of that league. “Syracuse always had big zones, but this team covers a ton.”
Moore, who handled the Rams’ scouting of the Blue Devils in the week before their potential second-round meeting, said the size he saw on film was so daunting that he told head coach Danny Hurley, “Whatever you do, don’t start watching Duke yet.” After beating Oklahoma in the first round, Hurley installed several new wrinkles to Rhode Island’s zone offense and then, as Moore said, “emptied the chest” during the game. Still the coaching staff felt helpless on the sideline, as even when the Rams got the ball into spots they wanted, Duke’s length and mobility made it hard to execute. Ultimately they scored just 0.91 points per possession, turning the ball over 13 times on 68 trips.
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“Most zone offenses have a component in there where you get it to the corner, the short corner, those are beneficial areas,” Moore said. “With them it’s almost like a Catch-22. You try to get it in there and you feel like it’s a success... They alter or block stuff that goes into those areas. So you’re left with three gaps up top and there’s 6’5” and 6’3” with long arms up top, and 6’6” too. Just not a lot of areas to attack it.”
It’s Carter, who occupies the middle of that back line, who Moore said is most key to the zone’s effectiveness. Moore likens him to a Venus flytrap for the way his patience around the basket practically lures opponents into attacking the rim, only for Carter to block or alter their shot. Carter’s 7.8% block rate on opponents’ two-point attempts ranked seventh in the ACC in this season, and while that may not match the 11.0% rate that eventual No. 2 overall draft pick Emeka Okafor posted for Connecticut’s national championship team in 2003-04, Carter’s style reminds Moore of his former pupil.
“He’s got the same trait that Emeka had,” said Moore. “He’s so big and long and he realizes that he doesn’t need to be quick off his feet. He can let you leave your feet and go up for your shot and he still has time to affect it.”
All of this—even Carter’s Okafor-like qualities—will be familiar to the man coaching against Duke on Friday, Syracuse’s Jim Boeheim. Krzyzewski began employing a 2-3 zone in part due to the influence of Boeheim, a good friend with whom he coached the U.S. national team for more than a decade and who has become synonymous with that defense, which this past weekend keyed 11th-seeded Syracuse’s upset of Michigan State. Three weeks ago the Orange were on the wrong side of the Duke zone’s stingiest performance to date, a 0.69 PPP smothering on Feb. 24, after which Boeheim joked, “I don’t think Coach K should be allowed to play zone.”
The zone he encounters this weekend will seem just as unfair, but it will not be the same. In the last week of the regular season, the Blue Devils added baseline and corner traps to their defensive arsenal; in their first-round win over Iona, they even deployed a 3-2 setup to disrupt the Gaels’ fleet of shooters. Duke’s coaches insist that they remain scheme-agnostic, ready to scrap the zone mid-game if needed, should it prove ineffective.
“We always could go back to man if we needed to,” Scheyer said. “But the zone’s been good for us. We just wanna continue to play it until—” and here Scheyer stopped himself, better this time of year to not contemplate when or why one would need cease doing anything. “Hopefully we just play it,” he concluded with a laugh. With the way it has looked, it’s reason to believe Duke will not stop playing soon.
