Robert Williams Injury Tests If Jayson Tatum, Celtics Ever Were For Real

Through the Boston Celtics’ meteoric rise this season, the prime beneficiary has been Jayson Tatum.

Tatum, the fourth-year superstar forward, has had his name come up in NBA Most Valuable Player conversations and prompted proposals to have Danny Ainge’s No. 44 jersey raised to the rafters due in large part to the former Celtics president of basketball operations swinging the deal that eventually landed Tatum and teammate Jaylen Brown. In averaging career highs across the board, Tatum has led the Celtics to the top of the Eastern Conference standings.

Yet while Tatum’s role has been more celebrated, Robert Williams has been almost as important to the Celtics’ midseason turnaround. And his extended absence due to a torn meniscus is so potentially injurious to Boston’s playoff hopes.

For all the explosion in advanced analytics in the past decade, the greatest emphasis still is placed on the traditional, countable statistics. Tatum scores the most points and takes the most shots, therefore his importance is easily understood. And when appreciation of Williams is expressed, it’s usually noted at the defensive end, where he leads Boston in blocked shots and rebounds.

The loss of Williams won’t only be felt at the defensive end, though.

To be sure, Williams is an elite defensive force. From a defensive efficiency standpoint, he’s comparable or even better than the likes of Joel Embiid or Rudy Gobert. He boasts a block percentage of 6.8%, which means he blocks about an estimated one out of every 14 shots the opponent takes when he’s on the court. That’s elite stuff.

But Williams’ impact on the offensive end is also considerable, and not exactly intangible, either. The popular phrase is, “it doesn’t show up on the stat sheet,” but thanks to today’s metrics, it absolutely does.

Williams’ offensive rating — or a measure of how many points his team generates per 100 possessions with him on the court — is 147.5. Not only is that the best on the Celtics, it’s among the best in the NBA. His true shooting percentage — which was developed to help even the playing field for guards by giving added weight to free throws and 3-pointers — is a Gobert-esque .745.

In fact, when offensive and defensive metrics are taken together, the only player who really compares to Williams at both ends is the incomparable Gobert.

By watching either play extensively, it’s easy to understand why. Although Williams is considerably shorter at 6-foot-9, the threat of him diving to the hoop on a pick-and-roll or sneaking in for a backdoor lob fundamentally alters the opposing defense. Help needs to be a couple beats slower to arrive when Tatum drives, because if the second defender steps up too soon, it’s an easy dish-and-dunk. On the perimeter, weakside defenders need to sag that extra couple feet away from Al Horford and Derrick White beyond the arc, because they know their bigs are going to need help with Williams around the hoop.

The Celtics know it, too.

“To have a guy like Rob, I mean, that’s just fun for me,” Horford told reporters last week. “Just throw it anywhere in the area of the backboard and he’s going to go up there and (get) it.”

This isn’t to say the Celtics will crumble without Williams or that Tatum’s stellar play merely has been a byproduct of Williams. Let’s not give Timelord that much credit.

But it does mean that the usual suspects like Daniel Theis, whom some observers proposed would need to step up in Williams’ absence, won’t be enough to offset what the Celtics lose.

Williams being out doesn’t just mean replacing 10 points and nine rebounds per game. It means dealing with an entirely new defensive approach by the opponent, and that now, more than ever, Tatum and the Celtics will be tested as to whether this season’s progress has been for real.