According to head coach Joe Mazzulla, three controllable issues can force the Celtics into transition defense (a place no player, coach, or basketball-trained golden retriever wants to be).
Turnovers are obvious. A sloppy pass or a lazy, exposed dribble will lead to a dunk more often than not. Even the worst NBA players are expert finishers when given a numbers advantage and a head start.
A missed layup is the scourge of transition defense everywhere. When a guy goes to the rack at full speed and misses, his momentum carries him out of the play and into the photographers (dangerously!) stationed feet from the baseline, giving the rebounding team an automatic numbers advantage. Players also often fall to protect their ankles and try to draw a foul. It takes a while to get back up, time the defense has used to collect the rock and race the other way.
Three is a bit more nuanced: offensive rebounders not crashing hard enough (or skulking along the baseline instead of curling toward the nail). That risks leaving a defender (or two) behind the ball and unable to get back in front of their man. It’s poor floor balance, as coaches like to say.
Mazzulla’s explanation was from January, but you know what? He had almost the exact same quote two days ago:
Mazzulla earlier this week attributed poor 2PT shooting, turnovers & crashers getting stuck in the corner for the #Celtics‘ transition defensive issues.
They’ve gotten wore tonight in a nightmare performance around the rim. pic.twitter.com/wNfYvLflhQ
— Bobby Manning (@RealBobManning) October 31, 2024
Unhappily, the repetition isn’t sinking in. According to Cleaning the Glass, which strips out garage time, the Celtics are currently 12th in transition defense (and 12th in transition defense frequency). That might not sound so bad — it’s slightly above average, after all! — but last year, they led the league in total transition defense and allowed the second-fewest transition opportunities. The Celtics are, speaking modestly, a nearly perfect basketball team, so slightly above average counts as a significant flaw.
Let’s use Mazzulla’s wisdom to break down why the Celtics are defending in transition so often this season. Of course, we’re still very much in small sample size territory, but if the Celtics want to be running on all cylinders, there are some engine parts to de-gunk first.
Live Ball Turnovers
As I mentioned at the top, nearly all players at this level are Wayne Gretzky on power plays, no matter who is between them and the basket. That’s why it’s essential Boston avoids sloppy turnovers like this:
Truthfully, annoying as they are to watch, live-ball turnovers aren’t a huge problem for Boston this season. They rank fifth in live-ball turnovers per game with just 6.4 (and they were second in this category last year!). Sure, there’s the occasional sloppy pass or mishandle, but that’s the price you pay for aggressive offense. Boston remains elite at this aspect of transition defense mitigation in the aggregate, although there are certain games where a few extra turnovers here and there can cause problems.
Missed layups
One of the secrets to Boston’s traditional transition-defense avoidance is that they’ve been a top-7 team in finishing at the rim over the last three seasons. Unsurprisingly, they’ve been a top-seven transition defense in that time frame, too.
This year, that trend has slowed a bit. Boston hasn’t converted particularly well, netting just 65.7% of attempts at the rim, 15th in the league and well below last year’s 70.5% mark.
Jaylen Brown, in particular, likes to charge in at full speed and then fall to avoid injuring himself and/or try to draw a foul. When the whistles go silent and the shot misses, the Celtics are left playing at a disadvantage:
Brown is normally unstoppable around the hoop, but he’s struggled at the rack this season (just 52%). This will correct itself over a larger sample but explains some of Boston’s transition defense struggles so far.
Lazy or inept offensive rebounding
This is a funny one. Offensive rebounding and transition defense have typically been basketball antonyms; prioritizing one usually comes at the expense of the other. But the tides are changing, and smart teams (hello, Boston!) have figured out how to do well at both. Just last year, the Celtics were an above-average offensive-rebounding team in addition to leading the league in transition defense.
But discipline and effort are required to pull it off. As Mazzulla mentioned in the soundbite above, there are two problems with crashing from the corners (something he admitted to doing more often this season). If corner players cut along the baseline for an offensive rebound that doesn’t work out, they end up on the wrong side of the ball, leading to an immediate fast break. And if players hover in the corner or dunker spot and are slow to react to the shot, well, they end up on the wrong side of the ball, leading to an immediate fast break.
That’s bad!
I don’t have hard numbers to back this one up, but you don’t have to watch too much Celtics film to figure out why Mazzulla is concerned. What is Tatum doing here in the last two minutes of a tied game?
He was frustrated after a non-call a bit earlier, but that’s the kind of on-court tantrum at a crucial time that would make any coach mad (and drive Mazzulla frothing-at-the-mouth rabid).
Or here, when Jaylen Brown weirdly takes a step along the baseline before casually jogging back from the corner after Xavier Tillman misses a driving layup (a double whammy!). While he’s crocheting in the corner, the Pacers have a 4-on-3 by the time the ball hits halfcourt:
Sure, the game isn’t close at that point, but we know how it ended! When you’re a team as good as Boston, every possession matters because anything can jumpstart a comeback.
So, how much is this really an issue?
Boston isn’t a live-ball-turnover machine. They are missing more layups than usual; that’s something to monitor, even if Brown will likely return to form. Perhaps the cramped confines drivers see as a result of Kristaps Porzingis’ injury are contributing, too. And as for the lazy/incorrect offensive rebounding? It’s hard to imagine a lack of discipline in the playoffs, although for a Celtics team with nothing to prove, it might pop up time and again in the regular season.
Boston doesn’t have many flaws, but that doesn’t mean they can ignore their relative weaknesses. Complacency isn’t part of Mazzulla’s playbook, and I expect Boston to tighten up as the season progresses.
