The Lion’s Mane

Posted by Ian Levy on March 17, 2011 under Commentary | 4 Comments to Read

Missing!

Ian Levy is the author of Hickory High, a contributor to Indy Cornrows, and a part of The Two Man Game family. He’ll be bringing his intelligent brand of — mostly quantitative — analysis here on a weekly basis. You can follow Ian on Twitter at @HickoryHigh.

A major storyline early in the season was the defensive performance of the Dallas Mavericks. Through November they were solidly in the top five in Defensive Rating. Since then, Dallas has slowly regressed to a Defensive Rating of 106.2, which ranks 12th in the league. The Mavs have been able to maintain their winning ways by becoming more efficient offensively and edging out their opponents in close games with terrific clutch performance, but playing up to their potential at the defensive end of the floor will obviously give Dallas the best chance of playoff success.

Earlier this week I got caught up looking at Ed Kupfer’s rolling averages charts and lost a significant chunk of an afternoon. In particular, I was intrigued by the way his graphics illustrated the steady decline in the Mavericks’ Defensive Rating. I set about to see if I could recreate his data and then identify some trends or events which might be contributing to their defensive inconsistency.

The chart below shows my version of the five game rolling averages for the Mavericks’ Defensive Rating. (A rolling average looks at the most recent data points to illustrate a trend. In this case each data point on the graph represents the average of the previous five games.)

Chart #1

The Mavericks’ defense peaked around their 19th game this season, a 93-81 victory on December 3rd against the Utah Jazz. Starting with their 34th game, an 84-81 victory on January 4th against the Portland Trail Blazers, the Mavericks’ Defensive Rating has gone through a dramatic series of peaks and valleys.

There are myriad factors which influenced the Mavericks’ strong defensive showing to open the season, as well as their subsequent roller coaster ride. Today we are going to focus in on just two of those factors. The table below again shows the five game rolling averages for the Mavericks’ Defensive Rating. You’ll notice that I’ve added a marker at the 29th game.

Chart #2

The 29th game which I marked was the last one Caron Butler played before suffering a season-ending knee injury. The contrast between the team’s defense before his injury and after his injury is pretty sharp on the graph. It shows up in the statistics as well.

When Butler suffered his (likely) season-ending injury, the Mavericks had posted a Defensive Rating of 103.6 to that point. Since then, the Mavericks’ Defensive Rating has swelled to 109.8. With Butler out of the lineup, the small forward minutes have been filled by a combination of DeShawn Stevenson, Sasha Pavlovic, Shawn Marion, Peja Stojakavic and most recently, Corey Brewer. Brewer has played limited minutes since joining the team and his defensive prowess hasn’t really materialized in any significant way. Shawn Marion is a solid defender but is slowing with age. The Mavericks are actually allowing more points with Marion on the floor this season then when he’s on the bench. Pavlovic, Stojakavic and Stevenson will never be confused with lockdown defenders. This is not exactly an ideal list of defensive replacement players.

The interesting thing is that despite having a reputation as a strong perimeter defender, Butler hasn’t done much to justify it in recent years. For the first four seasons of his career, Butler averaged an Individual Defensive Rating of 105.0. Of forwards who played at least 10,000 minutes over that stretch, Butler has the 15th best Defensive Rating and the 7th best Defensive Rating among forwards who spend at least some time defending perimeter players. From the 2006-2010 stretch of his career his Individual Defensive Rating grew to a worrisome 109.0, the 28th best mark among forwards with at least 10,000 minutes played.

In keeping with that theme: Butler was not very effective defensively with the Washington Wizards last season, giving up 0.92 points per possession overall, per Synergy Sports Technology. (Ed. note: Butler’s defensive numbers for the part of last season he spent with Dallas aren’t available through Synergy at the moment) However, his defensive numbers to start this season were terrific. Before his injury, Synergy Sports had tracked 237 individual defensive possessions for Caron Butler. Over those 237 he had allowed just 0.78 points per possession, the 42nd best mark in the league this season. The table below shows some of his numbers for each of those individual possession categories.

Possessiont Type% of Total PossessionsPoints per PossessionRankFG% AllowedTO%
Overall - 0.783936.9%13.1%
Isolation18.1%0.601735.5%23.3%
Pick-and-Roll Ball Handler9.3%0.68 - 42.9%27.3%
Post-Up9.3%0.91 - 50.0%13.6%
Pick-and-Roll Man0.4%2.00 - 100.0%0.0%
Spot-Up40.0%0.9211037.5%4.9%
Off Screen13.5%0.66730.8%15.6%
Hand Off5.9%0.43 - 18.2%14.3%

According to 82games, opposing small forwards were posting an eFG% of 46.3% against Butler and a PER of just 10.6 this year. As a team, the Mavericks have allowed opposing small forwards an eFG% of 48.1% and a PER of 13.2. Butler was statistically the team’s best perimeter defender, and the data confirms the observable improvement on that end that was so evident in Butler’s play. When Butler went down, the Mavs didn’t just lose a scorer — they lost a significant defensive weapon.

The second factor I wanted to look at was the impact Tyson Chandler. It didn’t even take the entire preseason for Chandler to win the starting center job from Brendan Haywood and his brand new 42 million dollar contract. Chandler quickly became the team’s interior anchor and was one of the reasons they got off to such a hot start at the defensive end of the floor.

Chandler has continued to have a strong defensive impact, but he’s struggled to stay on the floor at times due to a combination of injuries and foul trouble. The table below combines the five game rolling average for Defensive Rating we looked at above with the five game rolling average for Chandler’s minutes per game. I included games he missed in these calculations, counting them as zero minutes played.

Chart #3

For the most part, a decrease in Chandler’s minutes per game average has corresponded with a spike in the team’s Defensive Rating. When Chandler has been on the floor, the Mavs have posted a Defensive Rating of 104.1, which would rank 7th in the league. When he’s off the floor their Defensive Rating jumps to 107.6, just slightly above the league average. Simply put: Chandler’s presence takes Dallas from being a merely average defensive team to a very good one.

One of the areas in which Chandler has made a significant difference is on the defensive glass. According to 82games, the Mavericks have a DRB% of 73.1% when Chandler is on the floor and just 71.9% when he’s not in the game. His personal DRB% this season is 26.4%, the 15th best mark in the league. Chandler is the first major Mavericks’ contributor in the last 5 years with a DRB% over 25.0%.

For the first third of the season, Dallas was a formidable defensive squad, featuring the impact tandem of Tyson Chandler and Caron Butler controlling the paint and the perimeter. Since then, the team has vacillated between being average and terrible defensively. Butler won’t be returning, but the Mavericks still have hopes that Corey Brewer will be able to provide some of what Butler was giving them to start the year. The Mavericks are a top 10 team in terms of offensive efficiency but seven of the other top 10 offensive teams are potential playoff opponents in the Western Conference. For dreams of a deep playoff run to materialize, the Mavs will have to find a way to keep Tyson Chandler on the floor, slow down dominant perimeter scorers, and once again become a defensive dynamo.