Duke Blue Devils going back to small ball
Duke is unlocking Jayson Tatum’s potential — and the power of small ball — heading into the NCAA Tournament
It’s been a disjointed season for Duke, at best. We’ve all heard the typical beats — a never-ending rash of injuries, Grayson Allen’s flailing limbs, multiple back surgeries, and locker room pesudo-lockouts. Through the drama and scrutiny, Duke is still 24-8, and 9-3 in its last twelve. Though the Blue Devils lost three of their last four heading into the ACC tournament, the team as a cohesive unit looks to be rounding into form after a 3-4 start in ACC play, and they took down Clemson in their first ACC Tournament game.
Key in this late season push have been lineup shifts that push Jayson Tatum — the super frosh playing closest to preseason expectations — to power forward. Since the loss to North Carolina State on January 23rd, Tatum has played around 72 percent of his minutes with just one other “big” on the floor. The NC State loss marked the last time this season Duke put two traditional “bigs” in the starting lineup.
For the purposes of much of this analysis, that “big” group includes Amile Jefferson, Marques Bolden, Harry Giles and Chase Jeter, though reserves Antonio Vrankovic and Javin DeLaurier will figure into some portions.
Jayson Tatum – Power Forward?
The switch to small ball has been great for Tatum’s game. With more space to operate, he’s been averaging 15.6 points, 2.6 assists and 8 rebounds per game while shooting just under 40 percent from three. Prior to the Wake Forest game, Tatum had been hitting just 30 percent of his 3s.
Take a look at his individual shot charts from before the ‘switch,’ and since he’s been playing more power forward. As always, the shot charts follow methodology described at the bottom of this page. Tatum didn’t start playing until December 3, against Maine, and his individual charts will be missing the games before then, UNLV, and Boston College.
Though his activity near the rim has decreased, everything from the perimeter is working much better for him. Through his last 12 games, he’s hit 32 of his 84 shots (38 percent) 14 feet or more from the basket. While much of his scoring still comes through isolation, he’s looked significantly more comfortable operating on a floor spaced with three outside shooters. His assists per game have jumped from 1.8 to 2.5, with 55 percent of them coming on 3-point attempts. Despite perhaps the prototypical frame for playing small forward in the NBA, in a basketball world increasingly tilting toward small-ball, he may just be better suited at the 4 on offense.
Unlocking the Perimeter Guys
It’s not just Tatum who has offensively benefited from this switch, though. Up to and including the North Carolina State loss, Duke’s offense had been scoring a pedestrian (for them) 1.11 points per possession. Since the introduction of the “small” starting lineup, Duke’s been 5 points per 100 possessions better on offense, and per KenPom, will finish the regular season as the ACC’s 2nd-best offense.
Key to this improvement has been the offensive play from Duke’s guard rotation. Here’s a look at the collective shot chart of Grayson Allen, Luke Kennard, Frank Jackson and Matt Jones through the first seven games of ACC play (the game with Boston College is missing from the graphic).
While hot around the basket, the team’s group of four guards had work to do around the perimeter. The deep midrange game was non-existent, and the perimeter shooting lagged a bit, other than an extreme hot streak from the left wing. In all, the team’s guard rotation was hitting 37.4 percent from 3.
In the 12 games since shifting to small ball, though, their jumpers have been falling at a much better pace. Take a look at the aggregate shot chart, again for the four guards, below.
While efficiency has strangely dropped off a bit near the basket, the team’s perimeter players are raining fire from jump-shooting range. The group has hit 39.3 percent of its 3-pointers since they started small ball in earnest, and 45 percent of its 2-point jumpers outside the paint. Take a look at the table below, which compares individual player percentages before and after the small-ball switch.
Grayson Allen and Frank Jackson in particular have really benefited from the switch. Luke Kennard has stayed consistently excellent. And, while Matt Jones has struggled with his outside shot, the offense as a whole (per hooplens.com) has shot five percentage points better from deep while he’s been out there. He’s still willing to launch from deep, which can provide gravity value on its own.
Amile Jefferson, still the man
I’ve already spent plenty of words and research chasing down why you should love Amile Jefferson, the guy most often utilized as the single “big” during Duke’s recent small ball run. Despite a somewhat slow path from the bone bruise that held him out for a portion of the year, Jefferson continues to have the best plus-minus of the major rotation players on the team.
And he’s by far the best big to pair with Jayson Tatum, power forward. Check out the hooplens table, which includes the latest 12 game sample we’ve been discussing.
When Tatum and Jefferson share the floor as the only ‘bigs,’ the team is quite a bit better on both offense and defense than it has been in all other configurations. They’ve outscored ACC opponents by 10 points per 100 possessions, while actually operating in the negative in all other lineup configurations.
The Giles-Tatum pairing has been disastrously bad on defense, and while the Bolden-Tatum back line has been a positive, it covers just 38 total possessions — far too small a sample to be drawing big conclusions either way.
What the table above shows – and I haven’t exactly been drawing attention to yet – is how bad Duke’s been on defense during their recent 9-3 stretch. While the offense has been much improved when Tatum’s at power forward, the defense has been relatively awful. Duke’s been letting up 1.11 points per possession in its last 12 games, and KenPom’s conference-only numbers peg them as the 8th-best defense in the ACC.
The offense (and, likely, some luck) has been enough to let them win most of their close games in their most recent stretch of success. But history — not to mention their last four games — tells us all-offense, meh-defense isn’t the strongest formula for sustained success in the NCAA tournament.
Is Chase Jeter Duke’s 2nd Most Important Big Man?
Duke’s defensive slide could be traceable to one of the less-mentioned factors behind the switch to small ball — Chase Jeter’s back injury. The sophomore underwent surgery to address a herniated disc on January 23, and hasn’t been back to the lineup since. The timeline — or even possibility — of a return is murky at best at this point.
The easy answer is: who cares? The sophomore had been averaging just under 15 minutes and 3 points per game, numbers that seemed to be falling even more as Harry Giles and Marques Bolden worked their way back from injury. Duke’s big rotation was crowded before they started going small ball, and it’d be even worse if Jeter were available.
Check out the tables below, though. The first shows Duke’s margins in the last 12 games with 0, 1, or 2 bigs on the floor. The bigs could be any combination of Giles, Bolden, or Jefferson — Jeter hasn’t played in any of the last 12.
The only success Duke has been having is with a single big man on the floor. They’re getting significantly outscored when Tatum plays 5, or any two of their bigs are out there.
But this hasn’t been the case all year. Take a look at the table below, which does include Vrankovic and DeLaurier as potential bigs, as they were forced to pick up some spot minutes early in the year due to injuries.
Overall, Duke’s worst net margins on the year are with a single big. There are obvious dangers with pumping up the whole sample over 12 games against ACC opponents. Many of those games came in a non-conference schedule that ranked 159th in the country, and contained not a single true away game. Still, it shows — as reflected in the tiny sample from ACC play — that Duke’s played its strongest defense this year with two bigs on the floor.
The most successful 2-big pairings have included Chase Jeter. Here’s one last table (I promise) that stacks up 2-big lineups that contained Chase Jeter, and those that didn’t.
In similar samples, 2-big lineups that included Chase Jeter have been extremely successful on the offensive end, while maintaining solid efficiency on the defensive side. In all, 2-big pairings that included Jeter have been 11 points per 100 possessions more effective (in pure, unadjusted plus-minus) than all other combinations of Jefferson, Giles, Bolden, Vrankovic, and DeLaurier.
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I’d bet a good portion of this difference comes from the schedule Jeter played against; his plus-minus wasn’t world-beating against the non-cupcake opponents he faced (Kansas, Penn State, Rhode Island, Michigan State, Florida, and the first few games of ACC play). But in a season where Marques Bolden can’t get off the bench and Harry Giles plays less than 15 minutes per game, the Blue Devils need all the “big” help they can get. I’ll file it under “possibly interesting,” and hope that Jeter can make it back this year. Duke’s defense could use a boost if they’re going to do damage in the ACC or NCAA tournament.