The Long Two: Celtics without Robert Williams and the NBA Ironmen

With their most important player out for at least a month, it’s worth wondering whether the Celtics are still the same threat they were before Rob Williams’ injury.

The harshest reality in the NBA is that a team could spend months furiously coalescing into a juggernaut, only to be undone by a poorly-timed injury while playing its best basketball of the season. If Robert Williams’ torn left meniscus doesn’t push the Boston Celtics out of NBA championship contention, it at least moves them closer to the periphery of the conversation.

Boston’s center will reportedly miss four to six weeks after undergoing surgery on Wednesday, which could get him back on the court by the second round of the playoffs. But even that optimistic timeline rules Williams out for at least one playoff series, with no guarantee that he’ll be the same athletic force when he comes back. Now, it’s worth wondering whether the Celtics, who had won 24 of 33 games before Williams’ injury and established themselves as a legitimate contender, are still the threat they were just a few days ago.

How will the Celtics survive without Robert Williams?

Williams isn’t the Celtics’ best player, but he might be their most irreplaceable. At 6-foot-8 with a 7-foot-6 wingspan and explosive leaping ability, he’s the team’s most fearsome rim protector and only vertical threat on offense — skills for which there’s no real substitute. The Celtics have outscored their opponents by over 10 points per 100 possessions this season with him on the floor, with just a plus-2.8 margin when he sits. That’s a reflection of not only Williams’ wildly efficient individual production, but how the pressure he exerts at the rim changes the complexion of a game. Williams shoots almost 80 percent within four feet of the basket, and his 157 dunks this season ranked fourth in the NBA at the time of his injury.

That hyper-efficient interior scoring, and the way it warped defenses, helped Boston produce a 119 offensive rating with Williams on the court (filtering out the minutes he played with Dennis Schröder and Josh Richardson, who were traded in February) and eased the defensive focus on Jayson Tatum, Jaylen Brown and the team’s other creators. No other Celtic has the kind of bounce, catch radius or finishing ability to put that kind of pressure on defenses, which will not only undercut Boston’s inside scoring but allow defenders to better contain ball-handlers because they don’t have to worry about a lob to the rim. Williams is also a capable passer and is far and away the Celtics’ best offensive rebounder.

And yet, for all that he makes possible on offense, he’s even more crucial on the other end of the floor. The Celtics have been by far the best defense in the NBA since Jan. 1, mostly because Williams has become an absolute terror on that end of the floor. Opponents muster just 101 points per 100 possessions when Williams plays (again, without Schröder and Richardson) and a staggering 95 points per 100 when he’s shared the floor with Horford, Brown, Tatum and Marcus Smart.

While some of that is the result of poor opponent 3-point shooting, those five have undeniably been one of best defensive lineups in the NBA this season. Teams take just a quarter of their shots at the rim and get to the foul line significantly less often when Williams plays, and having that kind of shield at the rim allows perimeter defenders to more aggressively pressure the ball and challenge shooters out on the floor.

Lately, the Celtics had been deploying their rangy center in something of a one-man zone that kept him near the paint at almost all times while Al Horford, Daniel Theis or Grant Williams tracked more perimeter-oriented bigs. That allowed Williams to “guard” opponents’ worst offensive players (or whoever happened to be in the weak-side corner) so that he could stay in position to help at the rim more often:

If teams tried to pull him away from the rim by using his man as a screener, Williams would simply switch off of the screener and onto whoever was closest to the rim, and the Celtics quickly rotated into new matchups:

In addition to his prowess as a weak-side roamer, Williams was also one of the NBA’s preeminent drop and switch defenders against the pick-and-roll, which gave Ime Udoka the schematic flexibility to deploy virtually any coverage he wanted. Crucially, Williams’ ability to play alongside other big men could have allowed Boston to stick a center on Giannis Antetokounmpo or Joel Embiid in a playoff series and still keep a primary rim protector in the paint.

Losing such an integral pillar doesn’t just weaken the Celtics’ defense; it fundamentally changes how they defend, and the final six games of the season leave them little time to find a new approach before the playoffs.

Forcing the ball into the paint isn’t a tenable strategy if there isn’t an imposing shot-blocker waiting to block it; wings doggedly pressuring the ball becomes riskier without a firm safety net behind them. Boston still has a stable of excellent on-ball defenders and an adequate defensive frontcourt, and the Celtics may still be an effective playoff defense without Williams. But absent such a helpful offensive presence and indispensable defensive force, it’s hard to see them reaching the same playoff ceiling that seemed possible a week ago on either end of the floor. Horford and Daniel Theis are smart positional defenders, but neither has the athleticism to challenge shots at the rim or switch onto guards as well as Williams. Grant Williams provides more shooting and offensive versatility but doesn’t force defenses to account for him on either end the way Williams did.

Ideally, Williams will make a swift recovery and pick up exactly where he left off, cramming home alley-oops and swatting away shots as the backbone of one of the NBA’s most ferocious defensive units. Boston may have the wherewithal to win a first-round series even without him, and getting back a critical two-way piece may even provide a jolt in the midst of an arduous playoff run. All the Celtics can hope to do until then is adapt, survive and hope this interruption doesn’t cost them much ground.

A moment of appreciation for the NBA’s Ironmen

Between injuries, rest and cumulative wear-and-tear, it’s exceedingly rare for players in today’s NBA to play 82 games in a season — especially one in which 364 players spent time in the league’s health and safety protocols. That makes it all the more admirable that four players — Saddiq Bey, Franz Wagner, Dwight Powell and Kevon Looney — have appeared in every single one of their team’s contests thus far. Bey and Wagner have started all of those games, while Looney and Powell have been regular starters throughout the season, and all four have been given their respective teams a needed constant in a season of uncertainty. If all four finish the season having played all 82 games, it will be a testament not only to their durability (and, frankly, good fortune), but to their value on the court.

Particularly on playoff teams like the Warriors and Mavericks, players aren’t given rotation minutes unless they earn them, no matter what their availability. For Powell, that has meant filling a void at center in the starting lineup, sharpening his defensive reads and providing Luka Dončić a vertical threat in the pick-and-roll. After moving in and out of the starting five early in the season, Powell was re-inserted as a full-time starter on January 30 and has stuck ever since, giving Jason Kidd a reliable two-way big man who can finish above the rim and (sometimes) protect it on the other end of the floor. Powell is having the most efficient scoring season of his career as a play finisher next to Dončić, and while sixth man Maxi Kleber has clearly emerged as Dallas’ best center, Powell’s ability to soak up minutes at that spot bolsters the team’s depth and spares its other centers some of the grunt work he readily embraces.

Looney has performed an even better rendition of that dirty-work role, and while Golden State’s best playoff lineups will still feature Draymond Green at center (assuming the team is ever healthy again), Looney’s rugged play at center during the regular season has been critical to the Warriors’ success. Golden State has outscored its opponents by six points per 100 possessions with him on the court, and have maintained an above-average defense in the minutes Looney has played without Green. Watching Looney play can be fairly unexciting; he doesn’t generate offense for himself or make superhuman defensive plays, his usage rate is under 13 percent and he averages less than one block in 22 minutes per game. But getting 22 minutes of rock-solid center play every night has been immensely valuable for the Warriors this season, and Looney constantly creates subtle advantages on both ends of the floor — screening shooters open, slipping passes to cutters, gobbling up offensive boards and proactively positioning himself to take away easy shots for opponents. Though he looks slow-footed at times, Looney holds his own on switches and has become a reliable finisher around the rim as well.

For Bey and Wagner, this season has been more about getting developmental reps than contributing to a winning cause, but both players have taken advantage of the opportunity to stretch themselves. An audacious 3-point gunner his rookie year, Bey has dialed up his long-distance volume even further in his second season, though the rise in attempts has come with a drop in accuracy. Bey’s shot selection often walks a fine line between bold and ill-advised, and on the whole, he has been markedly less efficient this season. The tradeoff, however, is Bey developing a more diverse offensive game that could make him a cleaner long-term fit alongside Cade Cunningham. He has almost doubled his assist rate while reducing his turnovers, taken more shots at the rim and from mid-range, and improved his shooting percentage from every area of the floor but the 3-point line. Defensively, Bey has the tools of a multi-positional stopper, though he still needs to sharpen his awareness and decision-making on that end.

Wagner entered the league as polished a two-way player as one could reasonably expect a 20-year-old to be. Averaging 15 points on league-average efficiency, the rookie is already a reliable spot-up shooter with a decisive off-the-dribble game and has improved his playmaking chops since the start of the season. His usage and assist rates both rank in the 80th percentile or higher among forwards, per Cleaning the Glass, and Wagner’s off-ball defense is quite advanced for someone his age. Like most rookies, he’s been inconsistent and began to slow down before the All-Star break, and Wagner still has ample room for improvement. For now, he’s done more than enough to justify the Magic drafting him eighth overall, and made the most of every opportunity this season.