The Robert Williams conundrum

This afternoon, head coach Joe Mazzulla confirmed that the Celtics will indeed stick with the same starting five against the Heat, meaning they’ll continue to trot out a double-big lineup to start games with Robert Williams joining Al Horford.

When the Celtics inserted Williams into the starting lineup for Game 6 of their second round series against Philadelphia, the whole vibe changed. Increased minutes for Time Lord resulted in better rim protection, better rebounding, and more vertical pressure in the paint Even Joel Embiid credited Rob’s presence as the main deterrent to he and James Harden’s pick-and-roll game – the bread and butter of the Sixers offense.

What worked against Philly

Much of Williams’ success against Philly can be attributed to PJ Tucker being on the floor at the same time. Since Tucker spent 90% of offensive possessions sitting in the corner, Mazzulla was able to use Rob as a roaming rim protector; he barely had to worry about Tucker and could therefore focus on mucking up the paint. PJ had his moments – most notably an 11 point first quarter in Game 7 – but leaving him open proved to be largely effective because it inhibited Embiid from getting easy touches at the free throw line and it stopped Harden, Tyrese Maxey, and Tobias Harris from getting easy drives to the rim. Horford would essentially let Harden have a free drive into the lane – while instead taking away the pocket pass to Joel Embiid – because he knew Rob Williams was waiting to contest at the rim.

Here, Rob blows up the pick and roll by stunting at the pocket pass. Then, his length allows him to sit right in the driving gap, dissuading Embiid from attacking. If that were Derrick White or Malcolm Brogdon instead of Williams, Embiid might try his luck at taking Al off the dribble.

Embiid gets fairly deep into the paint but is STILL turned away from the hoop by Rob’s presence. It’s a perfect example of defensive rim protection that won’t show up in the stats (even in defensive rim FG% for the hoop psychos out there).

And, finally, an encapsulation of the Rob on PJ strategy. Williams completely ignores Tucker in the corner, and it results in a turnover when Embiid tries to pass it to him for the corner three.

Who does Rob guard on the Heat?

In last year’s Eastern Conference Finals, Williams spent the majority of his time guarding… wait… PJ Tucker? Yes, PJ Tucker was on the Heat, and Rob employed the same strategy against him that he did in games 6 and 7 of the Philly series. He’s the perfect player for Williams to defend because his lack of offensive threat allows Rob to roam on the backline and disrupt anything at the rim.

Photo by Michael Reaves/Getty Images

This year, though, the Heat don’t have a logical matchup for Rob in the starting lineup. He’s obviously not going to guard Jimmy Butler, Gabe Vincent, or Max Strus; I don’t need to explain why he won’t guard Jimmy, and he won’t guard Gabe or Max because they’re too quick and agile coming off of screens, both with and without the ball. Both of them are much more involved in the offense than Tucker was, so Rob won’t be able to just forget about them on the perimeter.

Then there’s Kevin Love. Love won’t move TOO much off the ball, but it’s quite dangerous to leave him open on the three-point line. He’s an absolute sniper, and helping off of him like we did against Tucker is making me nauseous just thinking about it. The Celtics can’t let him get hot – he’s three times the shooter PJ Tucker is.

So, that leaves Bam Adebayo. Bam loves to operate in the pick-and-roll; the Heat have run more pick-and-roll than all but one team in the playoffs (Atlanta), and Bam Adebayo runs more pick-and-roll as the roll man than all but one player in the playoffs (Deandre Ayton). And, unfortunately, Rob isn’t very good at defending the aforementioned pick-and-roll. Bam put up 30 against Rob during the regular season, and a lot of it came out of pick and short-roll shots.

This will become commonplace in the series if Rob guards Bam. We simply cannot afford it, and I think Joe probably knows that. Or at least he should by now.

The best Rob matchups off the bench

There are some logical matchups for Rob on Miami’s bench, which is where I think Rob SHOULD find the majority of his minutes in this series. First of all, Williams could play the typical bench center role and defend Cody Zeller; Zeller will run lots of pick-and-roll as well, but he simply isn’t as deadly in the short-roll as Bam, so I think the Celtics can get away with defending that action with Rob.

In terms of playing the roaming rim protector position, I think Williams would be effective guarding either Caleb Martin or Haywood Highsmith. Neither player is threatening behind the three-point line, and neither will be involved in the offense heavily, so Rob will be able to semi-ignore them on the perimeter.

Going with what’s working

Joe is going to go with the starting lineup that has worked for the last two games. The decision to bring Rob off the bench – despite being, in my opinion, the most logical way to find Williams meaningful, impactful minutes – would be met with a lot of opposition, and the safe decision is objectively to stay with what’s working. The Celtics held the Sixers to two straight games under 90 points, and it finally looks like their defense might have returned to form.

More important, though, is the opinions of the players. Smart, Brown, and many others have expressed (loudly and unapologetically) their admiration for the lineup change (and for Rob), and I think going against them would be met with a lot of scrutiny, both from within and outside the organization. That being said, Rob can still garner his 25+ minutes off the bench, so it’s just about justifying the change and why it should work, which I think could be a storyline after the first couple games of the series.

We’ll see how Rob fares guarding either Love or Bam, and we’ll see if Joe has the confidence and conviction to go back to Derrick White in the starting lineup. We could see a different C’s starting five by Game 3 — who knows? Maybe Rob learns how to defend the pick and roll within the next 24 hours. Probably wishful thinking, but we’ll see.