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Trevor Ariza: A Defense

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Given the way Trevor Ariza has played this year, yes, this is rather ambitious. But hopefully, at the end of this comprehensive look at Trevor Ariza's first 28 games, it will all make a little more sense.

Let's start with the area we're all familiar with- offense. Ariza simply isn't efficient from most areas of the floor. To begin, here's a look at where his shots generally come from:


The yellow (sorry, creole gold) numbers atop each bar represent Ariza's field goal % from that specific location. The bar heights themselves represent the percentage of total shots taken from that location. A breakdown of the breakdown:

  • <1 feet: this essentially translates to plays made at the rim. And this should come as something of a surprise: Trevor Ariza converts close to 70% of his attempts near the rim. The game-threads have been rife with complaints about Ariza's finishing abilities. Does this statistic negate those criticisms? Not necessarily. What it does mean is that Trevor Ariza doesn't often miss near the rim- he either makes the basket or, as is often the case, draws a foul (and then misses the free throws... but that's a topic for the next section). This also means that it would be wise for the Hornets to run plays with Ariza going towards the rim. The team needs to maximize how often he gets to the rim relative to how often he shoots.
  • 1-10 feet: This is the range from which Ariza puts up those awkward floaters. More often than not, his shots from 1-10 feet come as a direct result of drives he aborts half-way through. Careful observers will also note that his 1-10 foot shots often come off of his Euro-step/pull up short/fade move.
  • 10-15 feet: At first glance, it appears there's something strange happening here. Ariza is shooting better from this range than from locations immediately closer and further. But in actuality, it's entirely a function of small sample size. Ariza has only attempted 10 shots from 10-15 feet this year. Moreover, he shot 21% on 50 attempts from 10-15 feet last season.
  • 15-23 feet: Ah, the dreaded long two. This is the shot that had Houston Rockets fans screaming in agony last year. In 2009-2010, Ariza shot 156 long twos at 30% clip. He's cut down the rate a little bit this year, but it still accounts for a disturbingly large portion of his arsenal.
  • 23+ feet: Conventional logic dictates that if you're going to take the long two, you may as well step back and fire from three. Conventional logic does not apply here; Ariza should be doing neither of these things. Ever. Almost 40% (!) of Ariza's shots come from three. Of all players launching as many threes per possession as Ariza, he has the second worst three point percentage in the league.
Overall, the inefficiency of Ariza's shot distribution is obvious. About 54% of Ariza's attempts come from outside 16 feet. 

Ariza's shooting isn't any better in dead-ball situations- i.e., from the free throw line. Ariza does a decent enough job of getting to the line. His 3.1 FTA/36 minutes won't amaze anybody, but it's the fifth highest rate on the team (behind Paul, West, Jack, and Okafor). But his free throw percentages are just awful. At 69.1%, Ariza is actually exceeding his career free throw average by 3%. Running him off the ball and towards the hoop is still the most efficient way to employ him in the offense, but his free throw percentages raise the question: why even bother?

I won't criticize his offensive rebounding percentages (he's a career 6.1% on the offensive glass but 2.8% this season) because that's largely a function of Monty Williams' defensive system- encouraging players to get back and prevent transition opportunities. But from an overall perspective, Trevor Ariza has been severely detrimental to this team on offense. The overall statistical systems only confirm this.

Among all players that have played 20+ games this year (or 400 minutes), Trevor Ariza has the second worst Offensive Rating (points produced per possession- this incorporates points, rebounds, assists, turnovers, percentages, etc) in the NBA. In the three point era (1979 onwards), only one player averaging at least 10 field goal attempts per game has had a lower offensive rating (Denver rookie Mark Macon in 1991. Naturally, he finished All-Rookie second team). Trevor Ariza hasn't been bad at offense; he's been historically horrific. He hasn't just been the league's worst offensive player; there's a case to be made that he's having the worst offensive season in the last twenty years.

All of this, of course, leads back to my premise. How exactly is this even moderately a defense of Ariza when excoriation seems to be the word of the hour? The reason we acquired him- his defense.

As a starting point, let's sift through Ariza's primary defensive assignments this year and their offensive performances.

J. Salmons: 2-8, 5 pts, 4 turns
C. Anthony: 10-17, 24 pts, 3 turns
M. Ginobili: 8-19, 23 pts, 3 turns
K. Martin: 5-12, 18 pts, 4 turns
L. James: 6-16, 20 pts, 3 turns
J. Salmons: 4-11, 14 pts, 2 turns
R. Gomes: 4-9, 11 pts, 1 turn
N. Batum: 6-14, 14 pts, 2 turns
S. Marion: 2-6, 5 pts, 5 turns
C. Butler: 2-7, 5 pts, 1 turn
A. Jamison: 5-12, 20 pts, 1 turn
D. Greene: 6-15, 15 pts, 3 turns
A. Aminu: 6-11, 16 pts, 4 turns
A. Kirilenko: 0-6, 0 pts, 0 turns
N. Batum: 2-8, 5 pts, 0 turns
M. Ginobili: 8-17, 23 pts, 0 turns
K. Durant: 6-22, 26 pts, 3 turns
G. Wallace: 6-13, 18 pts, 1 turn
L. Fields: 2-5, 6 pts, 3 turns
M. Ginobili: 2-5, 8 pts, 1 turn
T. Prince: 2-8, 4 pts, 3 turns
K. Durant: 8-20, 25 pts, 2 turns
A. Iguodala: 5-7, 16 pts, 3 turns
L. James: 6-16, 20 pts, 5 turns
D. Greene: 3-8, 9 pts, 3 turns
A. Kirilenko: 3-9, 7 pts, 2 turns
C. Villanueva: 6-17, 17 pts, 3 turns
ed- Noticed that someone on the TD Hornets board attempts to point out that Prince scored 28 points in this game and thus invalidate the whole analysis. To which I'll just say: having logged every possession in that game, I can say quite confidently that the majority of Prince isos (and Detroit ran very few true isolations) came against Belinelli on switches when the Hornets played man. New Orleans also played zone for large sections of the second half, especially as the game wound down (and Ariza was ultimately responsible for Charlie on a number of such plays). But said commentator also repeatedly mentions how Ariza's play has been "$#!%" so he must be right!
D. Granger: 8-22, 27 pts, 1 turn

Scan through those, and you'll find not one crooked number in the bunch. Opponents simply do not shoot efficiently when they face Ariza. The most points he's ceded to a defensive assignment this year is 27 (Danny Granger on Monday, and Granger shot 36% for the game). On the year, exactly 2 of 28 defensive assignments have shot 50% or better against Ariza (Melo and Aminu). He's held LeBron James to 12-32 (37.5%) shooting and 4 turnovers a game. He's held Kevin Durant to 14-42 (33%) shooting. 

But how can we quantify this? We have a rather precise valuation of Ariza's offense; ORtg is an extremely good indicator of the offensive reality. DRtg, however, is largely a function of team play and can't be relied upon to accurately differentiate individual defensive players on a given team.

I was able to acquire the Synergy Sports player report on Ariza through 28 games. This is data that only NBA team front offices have access to (not the subscription-based service Synergy rolled out last year). And let's just say- the results are heartening. 

Keeping in mind that the NBA average points per possession is 106.6:

Ariza is an elite pick and roll defender- opponents average a mere 71.7 points per 100 possessions on which they play off a teammate's screen. He's an excellent isolation defender- opponents average just 92.2 points per 100 isolations. Opponents score 78.6 points per 100 possessions when they post him up. They manage just 65.5 points per 100 possessions when they come off screens to get the ball and score. Ariza has been exceedingly difficult to score on in virtually all offensive scenarios.

This is all to make no mention of Ariza's defensive rebounding- at a 17% defensive rebound rate, Ariza is top-10 for his position and one of the key reasons why New Orleans currently fields the second best defensive rebounding team in the NBA.

Overall, Ariza has been responsible for 317 total defensive possessions this year. On these possessions, he's ceded just 270 points. This equates to a rate of 85.2 points per 100 possessions. What does this mean?

The NBA player average points per possession is 106.6. Offensively, Ariza is at 90, which equates to a net -16.6. But defensively, he's at +21.4. And that's assuming he guards a league average player every single night, which (as the above list indicates) he clearly doesn't. Ariza is most often assigned to the opponent's most talented offensive player, making his net defensive value even higher. Overall, Ariza's defense has been more valuable than his negative offense. And when you consider the historic levels of incompetence on the offensive side, you begin to understand just how terrific he's been defensively. 

At 101.4 points allowed per 100 possessions, New Orleans currently has the 3rd best defense in the NBA. That simply doesn't happen without Trevor Ariza.


At the end of the day, none of this is to excuse Trevor Ariza's offensive play this year. He's been bad, and I won't sugarcoat that fact one bit. But he's also been absolutely stellar defensively. I don't think that gets pointed out enough by many of us here, including me. 

At some point, the team needs to correct for Ariza's inefficient shot distributions, his overall offensive inabilities, and Chris Paul's strange tendency to set him up for multiple threes each game. As long as he plays defense like this though, he's a net positive to the team and should be afforded the chance to turn things around offensively.