Celtics Losing Identity on Defense as Offense Emerges

The slippage began in the same quarter the Celtics built a 19-point lead. Ayo Dosunmu hit a three and DeMar DeRozan followed with a pair of jumpers over the drop, and the Bulls called timeout, not Boston.

Chicago had allowed 12 straight points in the other direction to Jayson Tatum and Jaylen Brown. An open floor game emerged. DeRozan, Dosunmu and Nikola Vucevic extended Chicago’s run to eight straight scoring possessions. Marcus Smart later admitted the Celtics took their foot off the gas, seeing their 19-point lead slip to 10 entering the second quarter. Joe Mazzulla didn’t call his first timeout until four minutes later when the Bulls took a lead on a poorly executed defensive handoff between Al Horford and Tatum guarding the pick-and-roll.

“I know in Chicago, they went on a great run, but I think at the same time, we were getting great shots,” Mazzulla said. “The same shots we made in the first half, we didn’t make in the second half. I thought our defense waned, and so in a situation like that, I probably could’ve done a better job of calling one and just building an awareness to what’s happening in the game. It’s a balance because I really trust our guys, I trust their maturity, I trust their experience and we’ve shown great poise.”

While Mazzulla transformed the Celtics’ offense into a fast-paced, active, screening machine that posted 118.3 points per 100 possessions through a 3-1 start (3rd), a training camp focused on that side of the ball, integrating new additions to the rotation and using a more drop-based scheme diminished the team’s defensive identity from last year. Boston ranks 24th in defense, allowing 120 points in consecutive games to the Magic and Bulls to fall to 117.0 points allowed per 100.

Between Monday’s ejection-filled meltdown in Chicago and Friday’s game against the Cavs, Boston received a day off and two practices to drill pick up points, communication and fundamentals. A hard pill to swallow for a group that built seamless connectivity and a scheme nobody in the league could break while the Celtics won 22-of-25 into the spring.

Now, a smaller lineup with thin center depth missing Robert Williams III hasn’t switched everything. They haven’t made offenses feel them. They’ve bended, pinching the lane and allowing the eighth-most wide open shots in the league. Some by design. Some through breakdowns.

“We were just a step slow,” Brogdon told CLNS Media on Wednesday. “(We) weren’t as physical as we had been the previous three games, but also there was some slippage in the in the Orlando game. It was just a game where we were more talented and able to pull it out. Having the slippage, and then it really showed in Chicago. We got to get back to being physical, especially on switches, and over-communicating like we had been previously.”

The Celtics spent training camp in more traditional coverages, dropping Al Horford, Luke Kornet, Noah Vonleh and Mfiondu Kabengele as they battled for opportunities. Kornet fell injured early, Blake Griffin signed after a long layoff and the team, outside of spot experimenting with ultra-small lineups, kept Grant Williams in a bench role guarding the perimeter. Vonleh eventually emerged as Horford’s backup, Derrick White won the starting job in place of Williams III and the Celtics started games switching along the perimeter with a big in a drop, before expanding that switching into late game lineups.

Brogdon expects the Celtics to keep that scheme and eventually build on it once he, Griffin, Vonleh, Sam Hauser and others grow more acclimated with it. They’ve played passively though, allowing jump shooters like Tyler Herro to break around screens and shoot over Boston’s center. Taking away the paint became a popular defensive technique in recent years, and the Celtics’ drop allowed the ninth-fewest shots per game (28.0) and worst efficiency (53.6%) inside of five feet.

In turn, Boston allowed the most mid-rangers per game (19.0) to opponents, which they hit at a high rate (48.7%). The Heat caught fire, finishing 11-for-18 on in-between shots in a narrow loss to the Celtics, but only hit 15-of-31 at the rim and 8-for-26 (30.8%) on threes. You can see how Boston wants to funnel ball-handlers into tough shots like one Jimmy Butler took here.

Ethan Fuller of Basketball News noted opponents find their rollers as rarely as any other team against Boston. That’s where the encouraging signs end.

Pick-and-roll ball handlers torched the Celtics for 1.04 points per possession and 57.9 EFG% so far. Their bigs have sat too deep in drop to impact drivers and without a clean switch open a lane while covering that roller.

The Celtics have turned opponents over at the second-lowest rate in the league (12%) after boasting the second most disruptive unit (14.3%) last year. Despite that, they’ve still allowed the 11th-most free throws per 100 possessions while White, Griffin, Vonleh, Smart and Grant have all fouled on over 4% of Boston’s plays early on.

“It’s definitely hard, but what our goals are and what we want to accomplish, we have to be able to (defend every possession),” Mazzulla said. “There’s going to be moments when it’s not perfect, but we have so much depth, we have to rely on someone to help get us out of those situations. We’ve done that in the first four games, then you can’t get bored with doing the right thing over and over again. That’s human nature, but it’s something we have to battle.”

Mazzulla expects to test more of his depth on Friday against Cleveland when Williams will serve a one-game suspension for making contact with an official. He wants the Celtics to fix their pick up points in the half court and address other fine details before making schematic or lineup changes, which may be required.

Kornet played briefly for the first time this season against Orlando, once a potential starter before an ankle injury derailed his camp. He played six minutes in the past two games where the Celtics allowed 108 points per 100 possessions, but struggled offensively as he committed a moving screen and split a pair of free throws while getting dunked on twice. Boston’s drop hasn’t proven active enough to impact opponents at the rim.

Horford amassed a 121.9 defensive rating through his first three games, resting against the Magic, while Vonleh fared better against second units with a 114.6 (+6.5 net). Vonleh showed some encouraging ability to cover ground and switch in training camp to earn his consistent minutes and a spot start against Orlando.

Horford and Vonleh played together briefly against the 76ers on opening night, Boston outscoring Philadelphia 23-20 during their seven minutes. Combining them could allow Horford to play the four and give the Celtics more size inside. It would also limit their offensive ceiling. Going small leaves the team without rim protection.

For Mazzulla, Boston doesn’t want to veer too far from their identity last year, but they’ve fixated on addressing their biggest weakness by playing small. That calls for a collective effort on the boards, connectivity along the perimeter and a willingness from Brown and Tatum to play physical defensive roles they’ve embraced as top shot blockers at their position. Those individual efforts drove the team to victory against the Heat despite their challenges navigating Bam Adebayo screens.

“For me, it’s about getting to the ball,” Brogdon said. “I think for all the guards. Getting to the ball so you can beat the ball screen so you don’t get hit. Especially if you know you’re not in the red, you’re not in a switch, your bigs aren’t in drop. You’ve got to be able to beat that ball screen and not let them get to, whether it’s a floater or a mid-range shot.”

“The best starting guards in our league can make those mid-range shots, so when you’re in a drop, that’s what you’re going to give up, but you still want to contest. You can’t let the ball-handler come down the court and really be starting their offense at the three or inside the three. You can’t keep backing up and giving space, giving room, so pick up points are all about being a step or two above the three-point line and picking the ball up early.”