Defensive Rebounding and The Celtics' Frontcourt

In Game 7 of the 2010 NBA Finals, the Lakers snagged 23 offensive rebounds and the Celtics gathered just 40 defensive rebounds. (So for the game, the Celtics defensive rebounding percentage was a sucktaculous 40 / (40 + 23) = 63.5%)  The painfully depleted frontcourt rotation for the Celtics -- Paul Pierce, Rasheed Wallace, Glen Davis, and a not-quite-healed Kevin Garnett -- could not hold Gasol (18 rebounds, 9 offensive), Kobe (15 rebounds, 4 offensive), and the rest of the Laker rebounders at bay.  Coming into this season, rebounding had to be an issue for the Celtics, especially with Kendrick Perkins injured and Rasheed Wallace retired.  In response to these needs, the Celtics acquired Shaquille and Jermaine O'Neal, but how would these players mesh into the overall rebounding success?  Jermaine has been injured most of the season, so analysis on that front would be spotty at best, but Shaquille has amassed enough playing time to make it worthy of a quick look.

Below are the regular-season numbers for the Celtics over last season and the first 23 games of the present campaign:

Boston Team Defensive Rebounding Percentage (DREB%):

• 2009-10:  73.8%, 14th in NBA
• 2010-11:  76.9%, 4th in NBA

Note that the league average for both seasons is 73.7% -- Boston was essentially at league average last season and they have since improved to elite status.  The primary reason:  Kevin Garnett.  It's hard to get through a broadcast of a Celtics' game without someone mentioning that "KG has his bounce back".  The stats back it up, too, as Garnett has improved from a 24.8 DREB% to a 31.3 DREB%.  The latter number, if he can maintain it, would be a career-high for KG, not bad considering that he led the league in this category from 2004 to 2007.  Kevin Love (who is having a historic year as a rebounder) and Marcus Camby sit ahead of him this year, so he is not currently leading the NBA, but he has been a fantastic defensive rebounder nonetheless.

The secondary reason for the improved Celtic rebounding is Shaquille O'Neal.  His DREB% for 2010-11 is 23.6, a level that would rank him 16th in the NBA, if he had played enough minutes to be eligible.  Given that Shaquille has a career average for DREB% of 23.7, he is performing right at his normal career rate.  In fact, Shaq has been a remarkably consistent rebounder over his career.  Instead of showing a rise-and-fall from youth to MVP status to old-age, the career trend is much more level than one might expect.  The pattern also applies to his offensive rebounding percentage (OREB%) and total rebounding percentage (TREB%).

Of course, Shaq's totals on a per-game basis are way down, because he is playing far fewer minutes at age 38.  But if playing time is factored out, Shaq is rebounding at a rate comparable not only to his career average, but also to his MVP season back in 2000.

Does elite rebounding translate into overall success?  A quick look at the top 2-player combinations on NBA.com shows that the Garnett-Shaq pairing has scored 631 points and allowed 491 points, for a +140 that ranks them as the 26th best two-man combo in the league.  However, on a per-minute basis, the numbers are even better.  The twosome has a +/- per minute average of 0.518, which would rank them second out of the top 50 overall +/- pairings.  The two players are rebounding well, but they are complementing each other areas, most notably on offense, with Garnett passing well and spreading the floor with his jump-shooting ability and O'Neal providing a premium low-post offensive threat.

Finally, how does Shaq compare to Kendrick Perkins, who is due to return from an injury-related absence later this season, most likely as O'Neal's replacement?  Too see the comparison, take the previous graph, tailor it to a shorter time frame, and indicate Perkins' rates with a dotted line.

With the exception of 2004 and 2008, O'Neal and Perkins have performed at approximately similar rates.  Given their injuries and current health status, choosing the better rebounder later this season is most likely going to be a matter of picking the healthier player.  O'Neal appears to be functioning as an equal replacement to Perkins on the glass, but given that Shaq has had to share the rebounds with an elite Garnett, Shaq may be outdoing Perkins by just a bit.