Both the Bucks and Bulls got noticeable help on the boards this summer, which got me wondering how the Bucks' rebounding may help or hinder their goal of improving on the 46-win 09/10 season. For starters, it's worth clarifying the Bucks' performance on the glass a year ago. While they were a decidedly mediocre 17th in both raw rebounding differential (+.16 rpg) and total rebound rate (the Bucks grabbed 50.2% of all available rebounds), those numbers obscure the very different stories that took place on the offensive and defensive ends. Offensively, the Bucks grabbed 26.2% of their own misses, good for just 18th in the league. Combine the Bucks' inability to get second chances with a general inability to make shots (25th in eFG% and 26th in TS%) and you have a nice little recipe for ineffective offense (23rd in the league).
Should we be really worried? Everyone agrees rebounding is important, so you'd guess that offensive rebounding would be a good indicator of team success. There's a reason it's one of Dean Oliver's famous "four factors," right? But looking at last season's stats suggest offensive rebounds may not be as important as you'd think. Exhibit A: by far the two best offensive rebounding teams in the league were Memphis (31.3%) and Detroit (30.3%)--teams that missed the playoffs and won just 40 and 27 games, respectively. Meanwhile, the Cavs, Magic, Celtics and Mavs were all among the ten worst teams in the league at collecting their own misses. What's also interesting is that for all those extra possessions they generated, the Grizzlies and Pistons weren't even decently efficient offensive teams--Memphis ranked 17th in offensive efficiency while the Pistons were 22nd.
In contrast, the top ten teams in defensive rebound rate (often expressed as opponent offensive rebound rate) were all playoff teams. Orlando (77.4%) edged Cleveland (77.2%) for the top spot, with the Bucks checking in an impressive third (76.4%). It's also no coincidence that the top ten in DRR closely mirror the top ten in overall defensive efficiency. Give the other team less chances to shoot and they'll score less. Rocket science, eh?
As we harped on a fair bit last season, the Bucks were excellent in terms of limiting opportunities (4th in opponent turnover rate, 3rd in defensive rebounding) but less impressive stopping opponents when they did get chances. The Bucks had the second worst opponent free throw rate in the league and were a good-but-not-great eighth in eFG% allowed. Still, it's hard to argue with the end result: the Bucks ranked second in defensive efficiency, and their work on the defensive glass was a huge reason why they were so difficult to score on.
Overall, the lack of correlation between offensive and defensive rebounding shouldn't be too surprising given the Bucks' defensive orientation. Do you think Scott Skiles (or any defensive-minded coach) wants his guys relentlessly crashing the offensive glass, or do you think he wants them getting back on defense? So even though offensive and defensive rebound rate are symmetrical in terms of their theoretical value, I'd guess that in practicality there's higher correlation between winning and defensive rebound rate than offensive rebound rate (if anyone has seen corroborating/refuting evidence, let me know). That also squares with the commonly-held belief that great defense is more important than great offense. And no, I have no long-term data to prove that, but I'll run with it anyway.
The defense-first philosophy is also reflected in most of the Bucks' individual numbers. Among PGs, Brandon Jennings was 12th in defensive rebound rate and 25th in offensive rebound rate. Carlos Delfino was 6th in DRR and 52nd in ORR--spotting up in the corners for threes clearly doesn't help your rebounding either. Ersan Ilyasova was 16th among PFs in DRR and 33rd in ORR. And among centers, Andrew Bogut was 9th in DRR and 26th in ORR.
The major exception was Luc Mbah a Moute, who led all small forwards in ORR but was just 25th in DRR. But that's less surprising when you consider that a) Luc's a garbageman on offense who often has little responsibility but to scrounge around in the paint for loose balls and b) he generally draws tough assignments on defense. Either he's guarding the opponent's best wing player or he's battling with a PF who's bigger than him, neither of which lend themselves to getting a ton of defensive boards. But what's especially fascinating is how much better the Bucks were on the glass with Luc in the game. Despite often playing as an undersized four, Mbah a Moute had by far the best on/off rebounding differential on the club--the Bucks grabbed over 3% more offensive rebounds and 2.9% more defensive boards with him on the court vs. off. That's pretty amazing given that Ilyasova is a better rebounder at PF and Delfino isn't too much worse at SF. So it's not like Luc was competing for minutes with terrible rebounders who made him look good. Does Luc's defense make his teammates better defensive rebounders? Quite possibly.
Looking ahead to 2011
So will the Bucks be better on the offensive or defensive glass in 10/11? At the very least they shouldn't be worse, and they obviously have some room to improve on the offensive glass. But much of it will come down to how Skiles distributes his minutes and whether Bogut is around to anchor the middle.
The first thing to consider is whether the new faces are better or worse than the guys they replace. In the backcourt, Keyon Dooling is a shockingly terrible rebounder for a guy with good size for his position, but Ridnour was also below average last season. Corey Maggette has always been a good rebounding SF, though his numbers the past two seasons may have been inflated by playing as a smallball PF. He's also not bad on the offensive glass considering he's usually the guy launching the initial shot. Chris Douglas-Roberts was a poor rebounder on both ends last year, but Jerry Stackhouse was just as bad.
Up front, Drew Gooden was marginally better than both Kurt Thomas and Dan Gadzuric a year ago and particularly good on the offensive boards. Among PFs, Gooden was 8th in ORR and 25th in DRR, ranking 11th in total rebound rate. Those numbers are clearly better than either Ilyasova or Mbah a Moute, so unless Gooden's forced to fill in for Bogut for a long period, the Bucks should be better on the boards no matter where they end up playing him. I'm not sure if he can actually defend centers, but at least he's shown he can rebound like one.
Jon Brockman might be the big x-factor, since it's not clear how exactly the Bucks will use him. Is he an undersized four or a really undersized five? Will he get 15-20 mpg every night or will he be a fringe guy? The one thing we know is that he'll rebound. Last year he led the league in ORR (18.2%) and was fifth in overall rebound rate (18.7%), though it will be interesting to see if he maintains that level on the offensive glass in a more defensive-oriented system. Given that the guards are usually the ones responsible for defending against leak-outs, I would guess guys like Brockman and Gooden don't see their numbers affected too drastically. And in case you're curious, Brockman's on/off effect was downright absurd last year. Though the Kings were actually worse on the defensive boards by 3%, their ORR ballooned by 12% when Brockman played.
Lastly there's Larry Sanders, who was an above-average rebounder on both ends in college. After watching him in Vegas, I'm not sure he'll immediately be a good NBA rebounder simply because he seemed to struggle holding position against NBA bigs. He also showed a preference for floating around the perimeter on offense rather than mixing it up underneath, so that might also limit his impact on the offensive glass. He's also active and hard-working, so he should be fine once he adds a few pounds to his long frame, but for now I'm hesitant to expect big rebounding numbers off the bat.
The other issue is distribution of playing time. The Bucks were a good defensive rebounding team in large part because they worked hard and had good rebounders at virtually every position. With the exception of Salmons, Ridnour, and Warrick, virtually all of the Bucks' regulars held their own on the defensive glass. Their best chance of improving on the offensive glass is if Brockman gets more time, though having Gooden in the rotation should also help. Still, it may not be worth improving on the offensive boards if it comes at a cost on the other end. And while the Bucks will no doubt be looking to improve offensively this year, the most obvious routes will be relying on Maggette and Salmons (for a full season) to draw more fouls and score more efficiently.
There's room to improve on offense--and the offensive boards--but at the end of the day we shouldn't kid ourselves. Every Scott Skiles team will be based on defense, and to maintain their high standards they'll also have to maintain their excellent work on the defensive glass. Fortunately they have the roster to do it and then some--now they just need to stay healthy.