BOSTON — Javonte Green had heard a lot about Robert Williams’ freakish athleticism even before the Boston Celtics summer league team came together in June. So when the duo got paired together in the first drill of the day, Green decided to see what the fuss was about and dialed up a lob. But the pass slipped out of his hand and sailed away from the intended target.

“The pass was crazy but Rob still caught it and dunked it. And with the left,” said an incredulous Green. "I was like, ‘OK, this is crazy. This is going to be fun.’”

This past weekend in San Antonio, Green got his first chance to throw a Rob Lob in an actual NBA game. The pass was better than that initial attempt but still sailed on him a bit. 

It didn’t matter. 

Williams soared to absurd heights. 6-foot-4 Spurs guard Derrick White is reaching upwards and his hand is below the waist of Williams, whose head is above the rim. LaMarcus Aldridge looks like a guard staring up at a soaring Williams.

"I guess it’s a cheat code for us,” shrugged Green.

The 22-year-old Williams produced maybe the best game of his NBA career in San Antonio, putting up 11 points on perfect 5-of-5 shooting, which included four alley-oop finishes (three dunks, one layup), to go along with seven rebounds and six blocks over 22 minutes.

It’s not a coincidence that Boston’s lob-success rate has spiked as Williams’ playing time increases. The joke used to be that the Celtics couldn’t throw a decent lob. Now, with Williams the target, the lobs don’t even have to be good.

 

Just ask Marcus Smart, who has assisted on a team-high six of Williams’ 20 alley-oop finishes over the past two seasons.

"All you gotta do is just throw it anywhere around the rim and he’s going to go get it,” said Smart. "It makes our lives a lot easier. You can pretty much throw it anywhere and he's at least going to give an effort, he’s going to get a touch on it or something.

"You got a guy like that on your team, it’s pretty hard not to throw the lob. You always want to throw a lob.”

Smart said that he actually has to remind himself at times to make the simple pass and not just throw it 15 feet in the air. He knows teams might eventually start trying to eliminate the lob, though it might not matter if Williams just leaps over everybody.

Smart believes the next step for Williams is honing his post game and expanding his range. Only one of Williams’ 57 career regular-season field goals has come outside of 10 feet (an 11-foot jumper in April against the Wizards). His average shot distance is a mere 2.4 feet for his career.

But it’s hard to argue with the results. Williams leads the NBA in offensive rating with the Celtics averaging 122 points per 100 possessions when he’s on the court. The next closest player is old friend Aron Baynes at 119.4 in Phoenix. His nearest teammate is Kemba Walker, who is fourth in the NBA at 118.5.

Williams’ rim-running ways is a threat at all times and defenses have to protect the basket, which leaves shooters open on the perimeter. Boston’s true shooting percentage spikes to 62.4 percent when Williams is on the court (well above their season average of 55.9). 

Still, maybe the most encouraging part of the Rob Lobfest in San Antonio was how Williams spent nearly six minutes defending centers Jakob Poeltl and LaMarcus Aldridge and didn’t allow a single point. Defensive consistency is one of the final barriers to a heftier role for Williams. Yes, those volleyball-spike blocks make for nice highlights but he’s trying to be more disciplined.

Still, teammates — both current and former — marvel at his potential. After Boston’s season-opening loss in Philadelphia, old friend Al Horford sought out Williams to tell him he sees a bright future ahead for the second-year big man.

“I admire Al a lot and I want to pick up a lot of stuff from him,” said Williams. “After that game, Al just told me some encouraging words. He told me to just stay healthy, stay ready.

"That was a great vet. That’s respect from a great vet in this league, and letting me know that other people see it in you, too. But that's Al Horford — like I said, I want to learn from his game a lot.”

 

Horford often gives up size on the back line but his basketball IQ makes him one of the league’s best big-man defenders. Williams is still watching Horford tape trying to learn from him. 

"I’m trying to become an all-around way better defensive player,” said Williams. “Just helping more on the defensive end, which — as far as being vocal, knowing when to slide over, knowing when to contest a shot, and knowing when to just go over with my hands up — a lot goes into it. Still working on it, but hopefully I’ll get there.”

Minor ailments have cropped up at bad times early in Williams’ career and sometimes prevented him from taking full advantage of opportunities. But with Boston’s murky big man situation, Williams is going to get every chance to increase his workload this season. He might just be the ideal fit alongside Boston’s core pieces like Smart, Kemba Walker, Jayson Tatum, and Jaylen Brown.

“He’s a very special talent,” said Walker. "His athleticism is unreal, he puts so much pressure on the rim. The thing that Rob has to understand is how important he is for us and how much of a role he can play for us. 

"I’m really happy for him. His work is showing over the course of the summer. He’s definitely reading the game really well. Like I said, he’s putting so much pressure on that rim for us.”

Yes, if teammates think Williams is a bit of a cheat code now, just imagine the possibilities as he unlocks even more levels in his game.

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Don’t miss NBC Sports Boston's coverage of Celtics-Wizards, which tips off Wednesday at 7:00 p.m. ET with Celtics Pregame Live, and then Mike & Tommy have the call of the game at 7:30 p.m. You can also stream the game through the MyTeams App.