The answer: 30th — dead last.
Let's be clear. The Celtics are far from the worst rebounding team in the NBA. Boston ranks near the bottom of the league, 23rd, in pace factor — a metric of how many possessions are played in their games, and the Celtics rank first in field goal percentage. Add that up, and there just aren't that many rebounds — particularly offensive rebounds — to be had. In fact, the Celtics actually out-rebound their opponents on the defensive glass, largely because their opponents miss more shots than they do, while they are out-rebounded on the offensive end arguably for the same reason.
Still, their 7.7 offensive rebounds per game, a .214 rebound rate on the attacking glass, is about as terrible as it gets. Even Miami, the team with no big men, beats that by 2.1 per game at 9.8.
How did that number dip so low? In truth, Boston was 30th on the offensive glass last season as well — though at 8.7 per game. The decline, though, can be attributed to a handful of individuals. Glen Davis, whose minutes have jumped by well over 50 percent this season, is rebounding on the offensive glass at about half of his per minute rate from the 2009-10 season. Despite the increase in court time, his offensive rebounds per game have decreased from 1.9 to 1.2. This can likely be explained by his transforming from a scrappy, below the basket forward to a mid-range jump shooter.
Davis, though, isn't alone. Paul Pierce, despite playing a forward position, now nabs just 0.4 offensive boards per game — as opposed to the 2.4 he brought down his rookie season. Shaquille O'Neal is taking down only 1.4 per game, a career low. Even Kevin Garnett, who has had a resurgent year and has added two defensive rebounds per game to his stats, has seen only an uptick of 0.1 per game on the offensive glass. Only Rajon Rondo — 1.2 to 1.5 per game — has seen a real increase in productivity crashing the boards. The Celtics' best offensive rebounder per minute? Jermaine O'Neal (1.1 in 17 mpg) — except that he never plays.
Obviously, Kendrick Perkins' return will help, but his offensive rebounding rate actually declined precipitously from 2008-09 (2.7) to 2009-10 (2.0), and it's hard to imagine him not being slightly less aggressive coming off an injury.
The Celtics are leading the Eastern Conference, so it's far from panic time, but come the playoffs, Boston won't be able to shoot at the same percentage, and teams will be crashing the boards against them with greater furor. Perhaps, Boston's older players are conserving their bodies for an offensive-rebounding push in the playoffs, but it seems more likely that Boston's older players just don't have the burst and physical power of their younger opponents.
Then, there's the matter of matchups. Against a team like Miami, won't the Celtics need as many extra possessions as possible? Won't they need to be able to counter-act the influence of Dwight Howard against Orlando? What about against Joakim Noah and Carlos Boozer? Or, of course, Pau Gasol, Andrew Bynum, Lamar Odom and the Lakers?
Playoff basketball has a way of turning into a brutal, ugly scrum. It's fought on the glass, particularly on the offensive boards. Boston may be rolling through the regular season and avoiding injury disasters, but when things get ugly, they'll have to do things differently.
Whether or not they can remains to be seen, but they surely haven't proven it yet.
Will rebounding be the Celtics' Achilles heel? Leave your thoughts below.