How, Where, and When Did the Trail Blazers Defense Get So Bad?

The Portland Trail Blazers’ 2020-21 season has been typified by two trends: mammoth scoring performances from All-Star guard Damian Lillard and an utter lack of defense. The former was expected; Lillard has been regarded among the NBA elite for several seasons. Acquiring forwards Robert Covington and Derrick Jones, Jr. at the start of the season was supposed to cure Portland’s defensive woes as well. It didn’t. Despite height, skills, and avowed focus on the issue, the Blazers remain among the most scored-upon teams in the league.

It’s easy to say that Portland’s defense is bad. Allowing 115 points per game speaks for itself. The more interesting questions are how, why, and when it got so bad. Portland fans are quick to point out the deficits in the defensive résumé of Head Coach Terry Stotts. Is the issue coaching-based, or could there be more to this story?

Today we’re going to take a look at Portland’s defensive numbers in several key categories over the last four years. from the 2017-18 season until today. We want to know which areas the Blazers are suffering in and when it started. This might give us perspective on their current, extended malaise.

For reference, here are the starting lineup and key subs for the Blazers between 2017 and now:

The starting guards have remained constant throughout the last four seasons. The power forward position has vacillated, but it’s been manned by a pair of defensive specialists in Al-Farouq Aminu and Robert Covington for three of the four years. (2019-20 was an exception, as Carmelo Anthony took over the spot before switching to the bench this season.)

Small forward has been shakier. Evan Turner, Moe Harkless, Kent Bazemore, and Derrick Jones, Jr. are middling defenders: not bad, but not game-changing. Trevor Ariza was Portland’s only acclaimed defender at the three over this period. He played but half a season.

The Blazers have also rotated through various centers over the last four years. Jusuf Nurkic was always their favored option in the middle, but a severe leg fracture in 2019 altered the course of his career. He sat out almost all of 2020, replaced by Hassan Whiteside. Nurkic returned this season, but he was not in the same shape and was soon sidelined by further injuries. Enes Kanter, a sub in 2019, stood in while Nurkic recovered.

Among the major bench players, Gary Trent, Jr. is the closest Portland has come to a prime defender. His claim to fame was willingness, and it was enough to make him a positive on the defensive end. He was hardly a stopper, though. Other than that, Kanter, Anthony, Anfernee Simons, and Shabazz Napier have filled big bench minutes. All struggle defensively.

Overall Efficiency

Here are Portland’s overall defensive efficiency ratings, along with their NBA rank, between 2017-2021.

The first thing you’ll notice is that...surprise! The Blazers used to be good at defense. Four years and 10 points per game ago, they ranked 6th in the NBA in defensive efficiency. Not coincidentally, 2017-18 was the season they ran deepest with defenders. It’s also the year they got swept by the New Orleans Pelicans in the playoffs in the first round, occasioning semi-drastic personnel and stylistic changes.

Even with those, they weren’t bad in 2018-19, ranking in the middle of the pack in Defensive Efficiency. One season later, they were in the basement. They haven’t emerged yet.

The most significant changes in that stretch have come at their big positions. Nurkic’s injuries kept him off the court. Anthony earned major minutes at the four spot. He and Nurkic’s replacements—Kanter and Whiteside—are all slower, ground-bound defenders. The Blazers managed to keep size on the court in Nurkic’s absence, but speed has eluded them.

On the Run

Few places has this lack of speed been more evident than in transition. Under Stotts, Portland’s mantra has been simple: don’t score a ton of fast-break points but don’t give up many either. Check out the numbers to see how that’s worked.

Up until 2019, the Blazers were pretty average in transition points allowed. The bottom fell out in 2019-20 as they plummeted to 25th in the league. Even though technically they allow a point less on the break this season, they’re still Bottom 5 in this category, ahead of only the Timberwolves, Rockets, and 76’ers.

In the Paint

If the Blazers have gotten bigger and slower, you’d think that would at least bode well for their ability to guard the paint. That’s not true this season.

This is one of the few instances in which a drop happened between 2019-20 and 2020-21 instead of a year sooner. For all his faults, Hassan Whiteside anchored Portland’s interior defense in a way that doesn’t appear to be happening this season.

That said, the actual 1.6 PPG difference between the last season and this is relatively small compared to the decline in other statistics. The real fall-off in Points in the Paint defense happened between 2017-18 and 2018-19, when the Blazers gave up a whopping 5.1 extra points inside over the course of a single season.

Overall Percentage

The story is largely the same when it comes to overall field goal percentage allowed.

Portland was great in 2017-18 and declined only marginally in the two years after. This season, they’ve gone all to heck, dropping from average—within shouting distance of good—to downright putrid. Whatever action NBA opponents are running against them, they’re not handling it. Combined with easy points given up on the break, it’s become a disaster.

At the Arc

If the Blazers are defending worse inside, you’d at least expect them to be able to defend the perimeter. Finally, blessedly, you’d be right.

As you can see, Portland’s three-point defense got downright horrific in 2019-20. They were average in percentage allowed from the arc two years ago, Top 10 in points allowed. Last year they could make a solid claim to being the worst team in the league defending the perimeter.

They’ve righted the ship somewhat this season, at least in terms of NBA rank. Their absolute numbers are still much worse than they were two years ago, but the league has also trended towards three-point shooting, which accounts for some of the increase in bulk attempts and makes.

Assist and Turnovers

As is typical, the Blazers have had mixed results in forcing turnovers and stopping opponent assists.

Generating turnovers has never been part of the Stotts defensive portfolio. The Blazers have flat-lined near the bottom of the league for most of his tenure.

When it comes to assists allowed, they experienced the now-familiar precipitous decline over the Summer of 2019. They used to be elite in this category. Now they’re mediocre at best.

Completing the Circle

Every successful defensive stop ends with a rebound. Defensive rebounding stats are overrated, but extremes at the high or low end can be indicative. Here’s Portland’s performance over the past four seasons.

This is virtually the only defensive stat in which we see a “yo-yo” effect. Portland was near the top of the league in 2017-18, went to nondescript territory the year after, sank into the doldrums in 2019-20, and then rebounded back to mediocrity this year. Part of it may be explained by the flimsiness of the stat. Rebounds are rebounds; teams are going to grab defensive boards because of positioning, pretty much no matter what. But it’s worth noting that the Blazers have seen the best and worst of the glass, and, for whatever reason, they’re not at either end anymore.

Conclusions

Defense is complex and notoriously resistant to statistical description. We can. however, make some broad claims about Portland’s defense based on these numbers.

1. The decline is not a new thing, and it certainly did not happen this season alone. The biggest defensive plunges came between the 2018-19 and 2019-20 seasons, with a couple significant ones happening a year earlier.
2. The most obvious roster difference during those critical decline years was simple: Jusuf Nurkic did not play. Zach Collins was out for much of that period too.
3. Portland’s defensive woes may not be attributable to individual defensive prowess alone. Frontcourt footspeed probably factors in. The shift from the fleeter pre-injury Nurkic and Collins to the much slower group of Whiteside, Anthony, and Kanter would explain Portland’s difficulty guarding in transition, getting in the passing lanes and, at least in 2019-20, getting out to guard the perimeter. Even a modest exchange of the infernally plodding (and occasionally disinterested) Whiteside for the Nurkic/Kanter duo could account for a positive uptick guarding the arc this season.
4. That modest increase in speed may not be enough. Though the Blazers have improved against the three-point shot, that’s pretty much all they’ve done. They allow opponents far more points in the paint this year than last, a much better overall field goal percentage, and a ton more assists per possession. This might suggest that though Portland’s frontcourt players are committed to getting out to the arc, they’re still not fast and agile enough to deal with the screens and/or cuts they face when they get there. The “show” appears to be working somewhat better than it did last season. The “recover” part of defense might be lacking.
5. Just as critically, if the frontcourt doesn’t improve the defense, there’s little backup. Portland’s smaller players are not stopping penetration, not generating turnovers, and seem fairly ineffective if and when they get back in transition.
6. If there’s a coaching issue here, it appears to be personnel-related as much as scheme-related. There’s no denying that four years ago, the Blazers were very good, maybe great, defensively. They had the same head coach, along with 3 of 5 of their current starters. It’s hard to believe that Al-Farouq Aminu was that much better of a defender than Robert Covington is. The same is true of Evan Turner and Moe Harkless versus Derrick Jones, Jr. and Norman Powell. But the center position isn’t the same anymore. The bench players either lack experience, agility, or defensive chops. Where the possibility of greater frontcourt speed (Harry Giles III) or wing competency (Nassir Little) exists, those players are buried behind veteran players with more cachet who, unfortunately, can’t bring it on the defensive end.
7. On the other hand, it’s worth asking if large doses of Little and Giles III would really cure what ails this team. Probably not. And that may be the issue. The Blazers appear damned if they do, damned if they don’t.

Either way, it’s evident that whatever is wrong with Portland’s defense is deep-seeded, not momentary. They’ve declined notably over the course of time. When they’ve fixed one issue, another has popped up, whack-a-mole style. That’s a sign of a defense stretched too thin.

Portland either needs Nurkic to return to full form or they need to get faster, more defensively-apt players to populate their frontcourt positions. Alternately, they could get more help in the backcourt, giving guard minutes to players who can stop penetration as well as the long shot.

If they don’t do any of those things, they won’t be able to fix their slow slide into defensive purgatory that started when Nurkic first went down and hasn’t ended yet.

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