We Need to Talk About Breanna Stewart’s Defense

Through the first two years of her WNBA career, Seattle Storm star Breanna Stewart is a case study in the limits of both our perceptions as fans and advanced analytics.

Read almost any story about Stewart’s on-court performance and her defense is bound to earn a graf or two. Even when Stewart is mentioned in passing, her contributions on the defensive end are likely to receive a mention.

It’s not hard to see why. Stewart ranked third in blocks per game (1.9) as a rookie and then sixth (1.6) in her second season. She finished runner-up to Sylvia Fowles in the 2016 Defensive Player of the Year voting, collecting eight votes. To put Stewart’s 1.7 blocks per game in perspective, only six players in WNBA history have averaged more blocks on a nightly basis over their careers.StewartBlockThe quintessential Breanna Stewart block—we’ll call it a Brenial™—arguably came in what was her fourth game as a pro. Bria Hartley beat Jewell Loyd and appeared to have a clear path to the basket on the baseline. However, Stewart reacted quickly to rotate over and swat Hartley’s attempt away with two hands.

Nobody would argue Stewart is an elite rim protector yet, but the consensus would seemingly have her among the WNBA’s better defenders.

That’s where the raw numbers diverge from Stewart’s perceived effectiveness.

Stewart’s 100.3 defensive rating was fourth-best on the Storm in 2016, but she slipped to eighth in 2017 after posting a 103.1 defensive rating. Among players who played at least 20 games and averaged 10 or more minutes per game, Stewart was tied for 78th in the WNBA in defensive rating in 2017. Even when she was DPOY runner-up, Stewart’s defensive rating was 48th when using the 20 games, 10 MPG standard.

On defensive rating alone, Stewart hasn’t been terrible, but she didn’t exactly hit an otherwordly level, either. Consider Crystal Langhorne has finished with a 99.8 and 103.2 defensive rating in each of the past two seasons. While Langhorne’s contributions are often underrated—something I’ve been guilty of—she’s not going to be lumped in with the WNBA’s best defenders anytime soon.

Of course, defensive rating alone doesn’t account for a player’s effectiveness at that end of the floor. Even if you dig a little deeper into the numbers, though, the results remain similarly mixed about Stewart’s defense.

As a rookie, she ranked in the 60th percentile in defensive points per possession (0.862), according to Synergy Sports. She also held opponents to 42 percent shooting in post-up situations, with her 0.864 PPP putting her in the 63rd percentile. On the whole, Stewart was a solid defender and seemed poised to take a step forward in 2017.

The problem is, Stewart noticeably regressed. She slipped to the 40th percentile in defensive PPP (0.912), and opponents shot 56 percent when matched up against her in post-ups. In general, Stewart allowed opposing players to score at least one point on 44 percent of her defensive possessions.

Granted, those numbers lack any context beyond the immediate circumstances of the shot itself. The Storm were a collective mess defensively in 2017, and one player being out of position has a domino effect for the rest of the team. Stewart may have also tried to overcompensate to either prevent a defensive breakdown or as a reaction to a defensive breakdown, which would’ve only proven to be counterproductive.

But the advanced metrics may not be far off in their assessment of Stewart. Put her against an elite scorer, and her flaws start to become apparent.

Here’s a few clips of the aforementioned Brittney Griner and Sylvia Fowles having their way with Stewart inside:Griner 2Griner 3GrinerFowles vs. Stewie 1Fowles vs. Stewie 3

Here’s Elena Delle Donne and Candace Parker getting the better of Stewart in isolation on the perimeter:Delle Donne 2Delle DonneCandace Parker

Jonquel Jones did a little of both when matched up against Stewart:Jonquel Jones Stewart 2Jonquel Jones Stewart 3Jonquel Jones Stewart

Now, it’s easy to make Stewart look bad by drawing attention to when she allowed her opponent to score, especially when isolating her against four All-Stars. But the numbers back up Stewart’s defensive struggles, and All-Stars are exactly who should be the measuring stick for Stewart. She has the talent to be an MVP, and she could very easily collect her first in 2018 if the Storm earn a top-four finish.

Generally speaking, Stewart is basically the inverse of Brittney Griner.

When Griner arrived in the WNBA in 2013, she was essentially an elite post defender already. She averaged 3.0 blocks per game and was in the 89th percentile in defensive PPP in post-ups. The following year, Griner blocked 3.8 shots per game, and she was in the 97th percentile in defending post-ups.

Offense was Griner’s weak area. Through her first four seasons, the Phoenix Mercury center was extremely effective with the ball close to the basket—averaging 14.9 points per game and shooting 56.3 percent from the field—but you couldn’t help but feel she still had another level to reach. The fact she was getting to the foul line a little over 4.1 times per game encapsulated that. With a little more savvy, Griner could draw more fouls.

Griner reached her offensive ceiling in 2017—if it isn’t lord help us. She averaged 21.9 points and 7.3 free throws per game. She acknowledged that improvement came after a change in attitude and playing style.

“I know how I played last year,” Griner said last September in an interview on the Mercury’s official site. “I know who pushed me around. I know who I couldn’t stand my ground as much against. Now, I stand my ground. I’m stronger with my two feet, not falling back and looking unbalanced, making stronger moves to the basket, getting more and-ones.”

Griner’s comments bring to mind the problem for Stewart.

Yes, Stewart ranked in the top 10 in blocks in her first two seasons, but that’s unquestionably to some extent due to the fact she’s 6’4″ and possesses the wingspan of an adolescent pterodactyl. She’s also athletic and can read the game well.

As Griner did in her first few seasons, Stewart still has plenty to learn. It took Griner four full years in the WNBA and playing overseas before she put everything together offensively. Maybe it takes Stewart that long, too. That wouldn’t prevent Stewart from being a top-10 or even top-five player in the WNBA in the meantime.

That’s why it’s scary to think Stewart can be an All-Star and All-WNBA second team player who was fourth and ninth in total win shares in her first two years despite being an average-to-good defensive player. Stewart is so good already, yet she still has a lot of growth potential.

Stewart is the Storm’s best player. When she’s having a bad game—be it offensively or defensively—it’s going to have a big impact on the team. Stewart’s progress—or lack thereof—on defense will be worth monitoring during the upcoming season.

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