How No Dirk Hurts Mavs Defense

The Mavs are saying Dirk (knee sprain) won't play tonight against visiting Portland. Some of the impact there is obvious, because The UberMan's offensive brilliance is so obvious. But here we study Nowitzki's surprising "game-changing'' effect on the defensive end as well:

In our First Impressions of the Mavs win in Cleveland , we noted the striking difference in opponent's field-goal percentage over the four games Dirk Nowitzki has missed in comparison to the rest of the season, and implied a level of impact his absence may have played in this difference.

This wasn't meant to directly compliment Dirk's man-on defense, or even his skills as a team defender, merely the impact his presence has on the defense as a whole.

When looking back, the instances for comparison have been few and far between. Meaning, the Mavs have been blessed by a high level of health from The Uberman … only further justifying that nickname.

As previously noted, over the four games Dirk has missed, Dallas opponent's have hit 48.5 percent of their shot attempts, compared to the 43.4 percent hit when he's taken part. An addendum to that is the fact that Dallas has also allowed almost a point per game more over that same stretch (94.25) than they have for the season (93.5) … despite the 84 points Toronto was held to.

Is this slip in the defense when Dirk sits a trend, or merely a statistical aberration? Frankly, due to the fact that Dirk hasn't missed enough games to create a large enough data pool to feed any deep evaluation, we're left with minor comparisons. So, take from this what you will.

Only twice in the past five seasons has Dirk missed more than one game. During the 2006-07 campaign he missed a whopping four, and in 2007-08 he missed five. He missed only one in each of 2005-06, 2008-09 and 2009-10.

First, here is the raw data this year and the previous five seasons:

Season

Games Missed

Pts. Allowed w/o Dirk

Avg. Pts. Allowed Season

Diff w/o Dirk

2010-11

4

94.25

93.5

-0.75

2009-10

1

95

99.3

4.3

2008-09

1

76

99.8

23.8

2007-08

5

104.2

95.9

-8.3

2006-07

4

94.25

92.8

-1.45

2005-06

1

85

93.1

8.1

One thing quickly jumps out in these numbers. When Dallas only has to survive one game without their best player, they have been able to compensate for his absence while showing no negative impact in the defensive numbers. In fact, it's been quite the opposite. They have shown a marked improvement for those single games. (The Wounded Tiger Theory?)

However, on those rare occasions Nowitzki has been kept from the court for extended stretches over the course of the season ("extended" by his standards), the defense has suffered. Since the 2005-06 season, if you weight the variances to a per-game level for the three periods of multiple games missed, making 13 games total, the Mavs have given up 3.9 points per game more when Dirk is not on the court.

Again, weighting the difference to break it down to a per-game level over those 13 games, they've also allowed their opponents to improve their shooting percentages to a minor degree, or by 0.98 percentage points.

This isn't a major change, yet it is often enough to ensure a jump of three to five places in season rankings. For example, lower the 43.4 percent Dallas is currently holding opponents to 42.4 percent and they leap from sixth to third.

Apply this same change to, say, Philadelphia and they move from ninth to third. Obviously, a full point over the course of the season means more than the same amount over 13 games, but it does illustrate that this "minor" change is still worth noting.

Here are the field-goal percentage numbers:

Season

Games Missed

FG% Allowed w/o Dirk

FG% Allowed Season

Diff w/o Dirk

2010-11

4

48.5

43.4

-5.1

2009-10

1

45.5

45.7

0.2

2008-09

1

38

45.5

7.5

2007-08

5

46.6

44.3

-2.3

2006-07

4

39.9

44.7

4.8

2005-06

1

47.2

44.3

-2.9

This isn't a vast shift in the performance of the team. Yet, it does seem to counter a commonly held opinion of Dirk, that he is a liability to the defensive effort as a whole.

The only span with more than one missed game in a season to see Dallas improve in field-goal percentage defense without Dirk, the four games in 2006-07, they opposed the second (Golden State), third (Denver playing without Carmelo Anthony, to be fair) and eighth (Sacramento) ranked scoring offenses … and managed to hold them an average of eight points below their season numbers in those three games.

If you use "defensive rating" (points allowed per 100 possessions), and apply some basic minute constraints (100 minimum minutes played this partial season, 1,000 minimum minutes for full seasons), since the 2005-06 season, Dirk has not finished lower than third on the Mavs roster. Meaning that statistically, he has been one of their three most effective defenders each year of that stretch.

One caveat to that is the fact that this is only considering the Dallas roster, a roster that hasn't always been flush with players known for their defensive prowess. And, being third on a single roster doesn't guarantee, or necessarily insinuate, a high league ranking.

We're not trying to unveil the revelation that Dirk is actually an elite defender. That's not the case. Again, we're only pointing to the fact that his presence has maintained a positive impact on that side of the floor, even if it doesn't always come directly from his individual defensive abilities.

If we're not presenting the argument that he is an exceptional defender, how do we explain the fact that the defense has shown a degree of slippage when he's not on the floor?

One possible explanation comes back to the offense, with a slight nod to the fact that he may not be the atrocious defender some have labeled him … a judgment he may have earned early in his career, but maybe has since left behind.

When Dirk is on the court, it allows guys like Shawn Marion, Tyson Chandler and Jason Kidd to conserve some of their finite amount of nightly energy at the offensive end because Dirk is always there to carry that load, to lean on. No one is being asked to "raise their level of play" or "step up" to fill the void left by his absence.

In reality, "raising one's level of play" or "stepping up" doesn't mean players are finding previously untapped reserves of energy and pushing their games to another level. Rather, they are being asked to sacrifice those moments within a game that could generally afford them a brief respite in an attempt to provide an offensive "spark." In other words, they may be giving up the ability to focus their energies on the goals defining their standard "roles" as they seek to fill the vacuum of a role left unfulfilled with Nowitzki's absence.

Put simply, if a player is no longer allowed the occasional play to rest as Dirk carries the offensive load, they may no longer be capable of maintaining their accustomed level of energy to expel in other areas. Thus, they raise their level of play in one area at the possible expense of another. Energy or focus is redirected rather than created beyond the breadth of a player's normal reach.

We would all like to believe players are able to go all out at 100-percent for every moment they are on the court. In reality, for the guys getting big minutes, that can't be the case at all times. Even Michael Jordan was accused of taking defensive possessions off in his prime. Observing these occurrences can be extremely frustrating, and there is a fine line between "needed" and "excessive" on-court breaks, but they do take place … because they must.

As Rick Carlisle noted, Dirk's mere presence is a "game changer." This is true on offense, where defenses must pay constant attention to him.

Tonight against Portland, the Dallas Mavericks – 25-8 but 1-3 without Nowitzki – will surely miss his offense. He is averaging an MVP-worthy 24.1 points and 7.4 rebounds while shooting 54.5 percent from the floor.

But no Dirk would appear to have ramifications at the other end as well. We'll never make the claim that he is the best defender on the floor, but that doesn't preclude him from having a positive impact merely by being there. … as the numbers prove.


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