Could Marcus Smart or Robert Williams win Defensive Player of the Year?

The Celtics have the NBA's best defense. Could one of their players win Defensive Player of the Year?

Marcus Smart defense
Boston Celtics center Robert Williams III tries to block a shot by New Orleans Pelicans forward Zion Williamson in 2021. AP Photo/Charles Krupa

Despite their shootout against the Nets on Sunday, the Celtics still have the NBA’s best defense by a narrow margin — edging out the Warriors or the Suns by a fraction of a percentage point (depending on how you feel about garbage time).

The Celtics’ defense has become a multi-faceted machine based on complex switching concepts.

“We don’t lack much as far as [defense], of course,” Ime Udoka said on Wednesday when asked a question about Payton Pritchard. “We have some big wings, and strong guards, and versatile bigs.”

That versatility plays an enormous role in the Celtics’ defensive success. It also complicates the conversation about end-of-season awards for the Celtics’ individual defenders, who are starting to chafe at the fact that their names aren’t mentioned more often.

At least online, the DPOY conversation seems to revolve primarily around Smart — who has long been the Celtics’ best defender and has made two All-Defense First Teams — and Williams, who is the backbone. On a team full of solid defenders, they both stand out.


A closer look at the stats shows a small advantage for Williams. In basic on/off stats, they are dead-locked — the defense as a whole gives up just under four points per 100 possessions fewer with each one individually on the floor. Williams’ defensive rating is slightly higher.

The NBA’s tracking stats are interesting, and a peek into why bigs usually win the award over guards. Smart contests more shots than the average guard, challenging 11.4 per game. Williams challenges 13.8, and his impact when contesting is far higher — opponents shoot 6.4 percent lower when his long arms are waving in their face. Inside six feet, the number jumps even higher — Williams’ opponents are expected to make 62.6 percent of their shots in that range, but when he challenges they make just 53.2 percent for a robust 9.4 percent differential.

In other words, Williams is highly impactful when an opponent has decided to get a shot off. Meanwhile, Smart’s contests have minimal impact statistically, particularly inside six feet.

Shots behind the arc seem like an opportunity for Smart to make up some ground, but that isn’t the case either — both contest roughly five 3-pointers per game, and Williams has a slightly higher impact closing out (opponents’ percentages dip 3.7 percent, as opposed to 3.1 when contested by Smart).


Of course, defensive impact is about much more than just contesting. Many of the NBA’s advanced metrics try to tackle defense, and while their success is debatable, the numbers are still worth noting.

In Estimated Plus/Minus — a metric that tries to account for random fluctuations in box-score plus/minus — Smart outstrips Williams comfortably and taps in at 10th in the NBA (Derrick White, for the record, is third). The number-crunching website FiveThirtyEight’s RAPTOR stat uses a formula to normalize on/off production, and it flips the advantage back to Williams by a hair. D-LEBRON attempts to adjust for luck and for a player’s role in its per-100-possessions statistical model, and Williams enjoys a sizable advantage over Smart.

Statistically, Williams does seem to have a bit of a head start. Still, defensive metrics are yet to catch up to their offensive counterparts, and they can’t entirely measure Smart’s impact.

For instance: How in the world do you measure the type of defensive awareness Smart displays here with numbers?

The split second Smart sees the initial kick-out pass is a little off, he starts running toward Kevin Huerter. By the time DeAndre Hunter saves the ball from going out of bounds, Smart is gathering to leap and tap it to Williams. Huerter never had a chance.


The Celtics’ bigs have an easier job in part because their guards help head off problems at the point of attack. They can switch easily not only because Williams and Al Horford can handle most ball-handlers, but also because players like Smart, White, and Jaylen Brown can guard up against bigger opponents. Defense is hard to measure — especially for a team like the Celtics — because it’s so symbiotic.

Case in point: A closer look at the metrics shows that from a pure impact perspective, neither Smart nor Williams ranks highest. Al Horford is above both of them in defensive rating, and he’s one of the league’s most impactful defenders in both RAPTOR (No. 7 in the NBA) and D-LEBRON (No. 3). Derrick White, meanwhile, ranks third in EPM. You could make a fairly strong argument that the Celtics’ most impactful defender overall this season is neither Smart nor Williams … but Horford.

So how will voters sort that out? There’s a chance they simply avoid the Celtics entirely — with too many good defenders to choose from, the assumption might simply be that the Celtics are a product of their own versatility and Ime Udoka’s defensive scheme (a case which, if a voter is consistent, should probably put Udoka in contention for Coach of the Year). A safer bet for DPOY would be Rudy Gobert, Draymond Green, or Giannis Antetkounmpo — the usual suspects from years past.

Still, you can bet on the Celtics if you want — Robert Williams currently has the fifth-best odds of winning DPOY in the NBA. But if you feel your money burning a hole in your pocket, keep in mind that chances are good the Celtics will split their own vote. Sticking to All-Defense selections might be safer.


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