Do the Boston Celtics have a rebounding problem?

The Boston Celtics’ offseason isn’t over, but it’s probably mostly complete. Landing All-Star wing Gordon Hayward was clearly the team’s most important move of the summer. It increased the Celtics’ ceiling substantially, and while it may not have made them a front runner for the Larry O’Brien trophy, or even for the Eastern Conference crown, it did inch them ever closer to title contention.

The move also added to Boston’s glut of perimeter players. After agreeing to a deal with Hayward, the Celtics were left with only two traditional big men beyond Al Horford, Ante Zizic and Gerschon Yabusele, both of whom are rookies, and as such they are relatively unknown commodities. The Celtics have been working to rebalance the roster since that point, swapping Avery Bradley for Marcus Morris and signing Aron Baynes in free agency.

Morris is more of a small forward than anything else, but he possesses the size needed to function as a nominal power forward. Baynes is a center through and through. Both players are big, strong, and more than willing to mix it up in the paint—the type of grinders Boston was sorely lacking down low last year.

For all of their toughness, though, it is still unclear if the Celtics have really solved the defensive rebounding troubles that plagued them last year. Boston gave up the fifth-most offensive rebounds per 100 possessions and ranked third from the bottom in defensive rebounding percentage (per Basketball Reference).

Baynes should help. He’s a solid on the glass, but he is the only above-average rebounder on the team when compared to the average NBA rotational bigs.*

*This was challenging to define, but the data it’s built out of includes any player classified as a power forward or center (or both) in Basketball Reference’s database that played at least 600 minutes, across a minimum of 35 games.

Clearly some of the players included here are at a disadvantage in being compared to an average NBA big. Crowder, Hayward, and Brown are all wing players. Still, all three will see time defending big men, either as a primary assignment or in switches, and as such, they will be responsible for attempting to keep them off the glass. That’s a reality of committing to a “positionless,” space-and-pace approach.

Boston’s path to overcoming its rebounding deficiencies is unclear, but there are essentially two thought processes to easing any anxiety they may produce. The first is that focusing exclusively on Boston’s bigs is too narrow of a view. The Celtics have several guards that rate as very good rebounders for their position, Terry Rozier and Marcus Smart chief among them. Hayward and Brown compare favorably as rebounders when viewed as guards as well, and both are likely to log time at the two.

It’s possible that Boston’s size around the perimeter (IT notwithstanding) will help lineups rebound more effectively. Perhaps the Celtics’ funky, versatile roster will allow the team to function as more than the sum of its parts. There’s potential for internal growth as well. Boston certainly saw that from Avery Bradley last year, so there is some precedent.

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It’s not hard to construct an argument that Morris’s numbers were deflated a bit by playing so many minutes on the wing and next to Andre Drummond, one of the league’s truly elite glass eaters. It’s possible he’s a better rebounder than he’s shown. It’s also possible that he’s not, though, and it’s hard to build a case that the Celtics will rebound the ball more effectively than each of their individual historical records suggest. That is to say, the evidence is not in their favor.

The better argument to make may be that it really doesn’t matter that much. Yes it’s frustrating to watch the likes of Tristan Thompson, Robin Lopez, and Marcin Gortat backtap missed shots to teammates for open threes. Those shots are often the juiciest of looks, and they can feel like back breakers when they occur at pivotal moments. But the cumulative effect of giving up a substantial number of offensive rebounds isn’t always as painful as it feels.

For the Celtics, and many similarly constructed offenses, surrendering offensive rebounds is a direct result from choosing to play small. It’s problematic if there is no counterbalance to that decision, but it is typically one that comes with expanded passing and driving lanes, and a wealth of associated open looks, often from beyond the arc. Those things generally outweigh a bump in opponents’ offensive rebounding effectiveness.

Boston has done the math and has deliberately chosen to focus less on cleaning up its opponents misses and more on maximizing its shot quality on the other end of the floor. They’re not alone in that.

Both Cleveland (11.3) and Golden State (11.7) actually surrendered slightly more offensive rebounds per 100 possessions than Boston (11.1) did last year. They too rely heavily on smaller, more versatile lineups, vulnerable to being punished on the boards. The Cavs’ and Warriors’ offensive firepower surpassed that of the Celtics, which made the decision to risk giving up second chances a bit more palatable, but the general principles remain the same.

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Boston was already beating opponents by going small. Choosing to double down on that strategy with as gifted an offensive player as Gordon Hayward, now in the fold, is something of a no-brainer. It’s entirely possible that his presence on the roster will do nothing to solve the team’s rebounding struggles, and the same may be true for Morris and Baynes, but as long as the Celtics continue to outscore opponents it’s not a problem.

So the next time Boston is playing against a marginal NBA center and he grabs a board after a miss, fires it back out to the three-point line, and watches as his teammate buries an open triple, don’t work yourself into a lather. Just remember, that for every offensive rebound the Celtics surrender for playing small and fast, there are a handful of open threes and easy layups. Those things are exceptionally valuable. Boston is right to prioritize them.