February 18, 2017 by J.H. Yeh
Last month, I did a research on how the team’s overall rim protection prowess is not a good predictor on the opponent’s field goal percentage at the rim because blocks can over-estimate young and athletics teams’ defensive performance. The New Orleans Pelicans are a good example because of their lack of experience, which results in them averaging 5.9 blocks per game (2nd in the league) but having the opponents to shoot 60.1% at the rim (20th in the league). This interesting phenomenon is a clear indication that shows blocks can over-estimate a team’s overall defense because young and athletic players can get up and block the shots but not skilled enough to play smart defense and efficiently protect the rim. On the other hand, the Utah Jazz are a team where blocks under-estimate their actual defensive ability. The Jazz average a modest 4.8 blocks per game as a team (15th in the league) but they are ranked second in the league in opponents’ shooting percentage at the rim by limiting them to just 55.5%. As a result, block is not a good metric to predict a team’s overall defense. Click here for the full article.
In this article, we will delve into the individual level since previously we discussed this topic on a team level. Blocks is a tricky metric since teams are oriented to play good team defense to be successful; however, most of the time, the majority of the defensive responsibility near the rim tend to fall on three to four players on a team.
Attached below is a list of players who are classified as center or power forward by the league. I have extracted their blocks per game, blocks per 36 minutes, and the opponents’ field goal percentage at the rim (5 feet or less). In order to ensure the players are having substantial impact on their respective teams, I have limited the list to 100 qualified players who have competed in at least 20 games and are averaging 15 minutes per game as of January 16, 2017. The average is 1.3 blocks per 36 minutes, 0.9 blocks per game, and holding on the opponents at 59.1% shooting at the rim. The statistics are courtesy of NBA’s player tracking.
This is the list based on blocks per game. Joel Embiid, Rudy Gobert, and Anthony Davis lead the pack by averaging 2.5 blocks per game.
Now the same list, but this is in order of their blocks per 36 minutes. In this list, Joel Embiid leads the league with 3.5 blocks per 36 minutes. Kyle O’Quinn is second with 3.2 blocks. Lucas Noguira is third with 2.9 blocks.
This time, I am sorting the same list in the order of opponents’ shooting percentage at the rim, from lowest to the highest. Unsurprisingly, Roy Hibbert leads the league and is the only player to hold the opponent to shoot under 50.0% at the rim. Surprisingly, Dewayne Dedmon is second at 53.7% and Trey Lyles is third at 54.0%.
In this list, judging on just the blocks alone, it is clear to ascertain Rudy Gobert is effective in both blocks and defending the rim. It is also apparent to see Larry Nance is not a good defender.
I’ve plotted the numbers into the chart below to create a scatter chart that shows the relationship between opponents’ FG% at the rim and blocks per game. With a very low R-Squared at 0.1226, the regression chart further validates that the two variables (blocks per game and the opp FG% at the rim) are not correlated.
We can easily see that blocks under-estimate players such as Hibbert, Dedmon, and Meyers Leonard. Hibbert may not be a surprise as he is an established veteran and a renowned rim defender. So far this season, he is averaging 1.0 block and limiting the opponents to 49.5% at the rim. Dedmon, a good discovery by the San Antonio Spurs, is averaging 0.8 block and holding the opponents to 53.7% at the rim. And Leonard, the fifth-year pro, is blocking 0.7 shots per game to go along with 54.5 opponent shooting percentage at the rim. These three players are the obvious outliers. They are the quintessential “heavy-footed defenders.” These players are skilled defenders who can timely and smartly utilize their instinct and size to gain good defensive position without elevating from the floor. They are great interior defenders who don’t block too many shots and are the exact type of players where blocks under-estimate. Heavy-footed players are much valuable than those player in which blocks over-estimate their defensive ability — and this is the very reason that allows them to stay around in the league because it is the skills that matter the most. Other heavy-footed defenders are James Johnson, Steven Adams, Ed Davis, and Zaza Pachulia.
On the other hand, Clint Capela and Karl-Anthony Towns are the obvious outliers in this category. Capela is averaging 1.3 blocks per game but giving up 63.5% of the basket at the rim. He is clearly not an effective rim protector despite his high blocks per 36 minutes (2.1).
And this is where we implement block per 36 minutes to get a better look at the relationship with opponents’ FG% at the rim (since players like Dedmon, Hibbert, and Leonard all play backup minutes). In the chart below, I replaced blocks per game with blocks per 36 minutes.
The result shows the same group of outliers — with Dedmon leading the group of heavy-footed defenders. Meanwhile, players like Clint Capela, Jahlil Okafor, and Montrezl Harrell lead the group of athletic bigs whose blocks over-estimate their rim protection skills. Generally, this department is led by young, athletic players who can block shots but are not mature enough to play effective defense around the rim. And that is okay, because it takes time and experience for a player to get better and wiser at playing defense in the interior. Other players whose block numbers over-estimate their rim protection are Gorgui Dieng and Anthony Davis. Nikola Vucevic and DeMarcus Cousins’ blocks also over-estimate their true defensive ability and this explains why some teams don’t value them as much as they value other bigs in the league. This same reason can also be justified for Serge Ibaka’s declining defense, which may expound for his reason of being traded twice in less than eight months.
On a side note, despite the small sample of games, I personally think it will be quite interesting to see the future development of Utah Jazz’s Trey Lyles. If my prediction is correct and Lyles continues to follow this trend without experiencing any major injuries, Lyles should go on to become a very good heavy-footed defender who can contribute solid interior defense to a playoff contender.
— J.H. Yeh
(all graphs are created by me, and all sources of stats are courtesy of NBA.com as of February 16, 2017)