In TV studios, on Twitter feeds and in living rooms across the greater Philadelphia area, people want to know: Why doesn’t Joel Embiid just destroy the Boston Celtics in the post? He’s unstoppable down there,1 after all, and Boston often appears to be at a significant size disadvantage.
So, why don’t we just see him do all the time what he did in the first quarters of Games 1 and 2?
Why does Embiid carry a field-goal percentage of just 44.1 in 17 regular-season and playoff games against Boston over the past three seasons2 but make shots at a 47.8 percent clip overall in that time frame? And why have the Sixers averaged only 1.049 points per possession against Boston on trips that include an Embiid post-up during that time — the fourth-worst figure they’ve recorded against the 21 opponents whom Embiid has posted at least 50 times?
You can blame Embiid himself for simply not being assertive enough. You can blame 76ers coach Brett Brown for not drawing up creative enough ways to get Embiid the ball in advantageous positions. (Only 45 of Embiid’s 194 post-ups against the Celtics since 2017-18 have come after one or more ball-reversals, per Second Spectrum.) You can blame the Sixers’ guards and wings for their seeming inability to throw simple entry passes. Blame whomever and whatever you want. But credit Boston’s defense as well.
During the Game 2 broadcast, TNT analyst Stan Van Gundy repeatedly made note of how Embiid was not getting his touches close enough to the rim. That’s a long-running trend. The Celtics have routinely forced Embiid to catch the ball farther away from the basket than he has against other teams, according to Second Spectrum data provided to FiveThirtyEight.3 His average post catch in all regular season and postseason games against non-Boston teams has come 13.8 feet away from the rim, compared with 14.5 feet in all games against Boston. (And it’s 14.9 feet in just the playoff games against Boston.) An extra foot or so might not seem like a lot, but it can be the difference between an easy layup and having to force a hook shot over the top of a defender.
In part because the Celtics are so good at pushing him off his spots, the Sixers have also taken longer to enter the ball to Embiid in the post against the Celtics than they have against other teams, typically waiting 3.1 seconds against the Celtics versus 2.7 seconds against other teams. And once Embiid actually gets the ball down low, the Celtics have done a better job avoiding fouls than other teams, fouling Embiid on only 14.4 percent of his post-ups compared with 18.5 percent against everyone else, per Second Spectrum. Boston has forced Embiid to pass the ball from the post more often as well, getting him to give it up 28.9 percent of the time, or 3.2 percentage points more often than he has passed against other teams.
So how does Boston deal with Embiid post-ups? Why do the strategies implemented by Brad Stevens and company give the Sixers trouble?
What Boston does is both simple and complex. The goal seems to be to force Embiid as far away from the rim as possible before he gets the ball; then, once he catches the ball, plant as many bodies as possible between Embiid and the rim. The Celtics are extraordinarily coordinated when it comes to executing pre-post-up switches. They know Embiid wants to post up, and they know the Sixers want Embiid to post up, so they contort themselves to ensure that he does not get too advantageous a matchup. (They’ll even switch during a post-up, and they can pull it off.) If at all possible, they want their center guarding Embiid when he finally touches the ball on the block.
In the clip above, Jayson Tatum and Enes Kanter flawlessly executed a switch on a back screen for Embiid, set by James Ennis. It helped that they knew Ennis was not the target of the play, so they could just ignore him. Tatum let Ennis set his screen and cut to the opposite side of the court, and Tatum barely moved. He stayed where he was so he could bump Embiid on his way down and give Kanter time to recover to the block. Then, as soon as Embiid caught and turned to face the rim, Marcus Smart was right there to double-team and force a deflection. This, too, is a trend: Boston has sent a double team at Embiid in the post 20 percent more often than the other 28 teams in the league over the past three seasons, per Second Spectrum.4
If the Celtics can’t get their center to Embiid by the time the entry pass is teed up, then they switch off the ball to make sure the center is helping underneath the rim rather than stuck on the perimeter. In the clip below, Gordon Hayward, Jaylen Brown and Daniel Theis executed a three-way switch so that even though Embiid was posting the much smaller Brown, the Celtics could feel comfortable knowing that Theis was the one providing help near the rim.
It helped the Celtics there that the Sixers had Ben Simmons, who is not a jump-shooting threat, as one of the two players already on the weak side, which is how Theis could feel comfortable not guarding Harris at all as he made his way across the floor. Without many shooters on the floor, the Celtics had the freedom to execute the rest of their plan.
If Embiid even steps foot in the paint, the nearest help defender slides over to deny an entry pass until the man guarding Embiid can steel himself enough to force Embiid off his spot. Once they manage to push him farther away from the basket, the Celtics do absolutely everything they can to ignore the non-shooters. In the montage below, pay attention to how many times two Celtics were defending three Sixers on the weak side while two were on Embiid. Simmons, Al Horford, Matisse Thybulle … anyone who isn’t a plus shooter gets the full Tony Allen treatment.
What the Celtics want to avoid is Embiid just backing his man into the stanchion and easily laying it in. Once they get him far enough out on the floor that he has to turn and face the rim, whoever is guarding the Sixer one pass away from Embiid shades help toward him. If Embiid puts it on the floor, the helper comes all the way over, and everyone else shifts position accordingly. It’s a lot of work, designed to make Embiid himself put in a lot of work to get the ball in the basket.
The Sixers, of course, know all this, and so does Embiid. They have been seeing it in action for several years now. They have occasionally shown a willingness to swing the ball side-to-side and get Embiid good position on duck-ins, but that willingness tends not to last, and before long they are back straining to make entry passes on stagnant post-ups.
Now down 2-0 in the series, the Sixers need to find some answers. Against Boston, they’re unlikely to come all that easily.
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