Are the Blazers Getting Better at Fouling?

The Portland Trail Blazers, in the years since moving on from LaMarcus Aldridge to Damian Lillard, have ranked near the bottom of the league in the number of fouls committed per game. They have also remained in the bottom 10 percent in the number of free throw attempts their opponents are allowed. Then, in their third post-Aldridge year, the Trail Blazers bumped up to the middle of the league in these categories.

On the surface this seems like a significant improvement, which begs the question: Are the Blazers really getting better at fouling?

One noteworthy development during the 2018 season was that the Trail Blazers hired former NBA/WNBA referee Don Vaden. In a January article by NBC Sports Northwest’s Jason Quick, we learned that a big portion of Vaden’s emphasis was on improving the relationships and understanding between the players and the refs. However, one might also infer that working with a former referee could help the players reduce the number of fouls called against them.

Overall fouls committed

Comparing the 2017 to 2018 season, the Blazers reduced their average number of fouls per game by 1.7 (via stats.nba.com). That is the third-best “improvement” among all teams, behind the Phoenix Suns who reduced the number of fouls committed by a whopping 2.8 and Minnesota who committed 1.9 fewer fouls per game.

How does this break down before and after the Blazers hired Don Vaden in mid-January? For the first three months of the season (October-December), before Vaden joined them, the Trail Blazers averaged 20.03 fouls per game. That went down slightly to 19.45 for January through April during Vaden’s residency.

Fouls committed by individual players

The team reduced the number of fouls committed on the whole, but how did the individual players do?

Per game: Nearly everyone reduced how many fouls they committed before Jan. 15 versus after. The only rotation players who did not reduce the number of fouls they committed were Jusuf Nurkic and Maurice Harkless. This chart shows all players, sorted by the biggest improvement.

Because of the variability in playing time among the players, I also looked at the number of fouls committed per 100 possessions. That way we can more accurately compare players who play more minutes with those who play less.

Per 100 possessions: In this view, you can see that among the rotation players, Zach Collins made the biggest strides in reducing the number of personal fouls per 100 possessions before and after Jan. 15. Collins went from committing 7.4 to 5.7 per game. Maurice Harkless, Jusuf Nurkic and Pat Connaugton each slightly increased the number of fouls they committed.

It is a good sign to see that Zach Collins is fouling less. As a rookie whose playing time increased as the season went on, it seems impressive that the number of fouls he committed steadily decreased, from a whopping 16.7 per 100 in October down to 4.7 in April. Collins was also known for his high foul rate in college with almost three personal fouls a game; he even fouled out in the National Championship against UNC.

What kinds of fouls are they committing?

It seems unlikely that a team in the modern NBA would make it through an entire game without committing a foul. If teams didn’t foul we would probably ask: Why were they not more aggressive?

That having been said, most informed NBA observers know the difference between a “good foul” and a “what was he thinking?” foul. So, along with a reduced number of fouls from the Blazers this year, can we see any improvement in the types of fouls they are committing?

Shooting Fouls

Since shooting fouls result in trips to the line for the opponent, let’s start by looking at how many of these types of fouls the rotation players committed. Basketball Reference records the total number of shooting fouls committed by each player. Good news: almost everyone improved from this season to last.

Because the playing time varied considerably from season to season due to injury (Ed Davis, Al-Farouq Aminu) or having earned more time in the regular rotation (Pat Connaughton, Shabazz Napier) I averaged out the number of shooting fouls per minute played. This chart shows the number of shooting fouls per minute from 2017 to 2018 seasons. They are listed in order of who showed the most improvement. (Basketball Reference does not list shooting fouls for college, so I don’t have those numbers for Zach Collins.)

Only Al-Farouq Aminu committed (slightly) more shooting fouls per minute. Kudos to Ed Davis for an improvement of .03 fouls per minute. That averages out to 1.08 less shooting fouls per 36 min. It will be interesting to see if Zach Collins improves next season.

Offensive fouls

Offensive fouls are turnovers; they take the ball out of the Blazers’ hands and send the action the other way. How are they faring in the number of offensive fouls committed? During the 2017 season, the Blazers committed 129 offensive fouls. In 2018, that number rose slightly to 135. What happened?

Jusuf Nurkic committed the most offensive fouls on the team by a wide margin: 43 compared to the next greatest offender, Ed Davis (who had 24). The previous season, during his combined time with Denver and Portland, Nurkic committed 30 offensive fouls. He also played fewer minutes: 1,391 in 2017 versus 2,088 in 2018, approximately a 50 percent increase. That averages out to approximately the same per/MIN rate of .021 vs .020. So more minutes for Jusuf Nurkic probably caused much of this uptick for the team overall. (An interesting coincidence: Allen Crabbe, Noah Vonleh and Mason Plumlee last season combined for 43 offensive fouls between them. I only bring this up to reinforce that Nurkic has much room to improve and if he can show improvement, overall the team will show significant improvement.)

While Nurkic’s overall number of offensive fouls increased, both Damian Lillard and CJ McCollum reduced the number that they committed by less than half. It is a small number of fouls but for players who have the ball in their hands a lot and perform a lot of plays in isolation, this is a good trend.

Shooting fouls and offensive fouls as a percentage of overall fouls

One way to decide if the Blazers are fouling smarter is to look at if they are reducing the number of fouls which result in their opponents getting to the line or resulting in turnovers as a percentage of their overall fouls. This seems to be the case. From 2017 to 2018 the percentage of Shooting and Offensive fouls called on the Blazers dropped from 60 percent of the total fouls to 57.6 percent.

Conclusion

It seems like the Blazers are indeed making progress in reducing the overall number of fouls committed and are also getting more judicious about shooting and offensive fouls. It is possible some of the improvement was due to the Blazers’ new relationship with referee consultant Don Vaden since there were significant improvement from several players after his arrival. In particular, Zach Collins — whom Vaden said had a fundamentally solid defensive style of vertically challenging shots — improved to the point that he was no more prone to fouling (5.9) than the other bigs in the rotation, Jusuf Nurkic (5.8) and Ed Davis (6.5).

Regular season stats paint a picture of a team that has indeed reduced the number of fouls they commit and subsequently limited the number of times their opponent got to the line. It’s not hard to see how avoiding an unwanted foul in a number of close games may have helped contribute to the Trail Blazers’ improved regular season record. This look does not take into account playoff numbers (this is where I would insert a joke about small sample sizes). A possible next step would be to see if the Blazers reverted to any old habits or showed a different pattern in the playoffs.