It was a simple baseline cut off the right corner for an alley-oop, in which the defense overloads to a Westbrook pick-and-roll and completely forgets about Roberson. It's a set the Thunder, and Roberson, have worked at for years, taking advantage of opposing defenses not guarding him, turning what is supposed to be a weakness into a strength.
Roberson knifed to the rim, Westbrook put up the lob with the Thunder up 25 points on the Detroit Pistons, and what appeared to be a slip on a wet spot turned out to be a noncontact knee buckle. Season-ending surgery to repair a ruptured patellar tendon came shortly after.
The Thunder went on to beat the Pistons and rallied to beat the 76ers a day later for an eighth straight win, but the residual effect of losing Roberson, both physically and emotionally, has caught up. They've dropped four straight, with Roberson's current starting replacement, 19-year-old rookie Terrance Ferguson, scoring two points on four total shots in the five games. With Ferguson, the Thunder starters are a minus-11.3 points per 100 possessions, while the starters with Roberson were a plus-14.2.
Thunder coach Billy Donovan hinted at a starting lineup change for Tuesday's matchup with the Golden State Warriors, but none of the options is especially great.
"I just think I have to evaluate it," Donovan said. "We've lost four games in a row. My job is to try and look at what's best for our team. I'm not saying I'm going to [make a switch], but I have to look at all those things right now."
It's ironic that the Thunder appear affected so drastically by the absence of Roberson when the past few seasons featured plenty of hand-wringing and griping about the one-way specialist.
Roberson is truly elite on the defensive end -- he was building a sturdy case for defensive player of the year this season -- and was not quite the negative he was perceived to be offensively. He can't shoot (8-of-36 from 3 on the season) and his free throw ineptitude can force him off the floor when teams want to hack him, but as a screener and cutter, Roberson is an effective piece, especially when playing alongside offensive stars like Westbrook, Paul George and Carmelo Anthony.
Roberson is unique, a role player in every sense of the word, embracing his job and playing it to an elite level. And within the context of this Thunder roster, he fit. His deficiencies are largely masked, and the team has learned how to play around them.
It's not that the Thunder have dropped off a cliff defensively, though (they remain No. 5 in defensive efficiency). In the four-game losing streak they're allowing 106.1 points per 100, compared with 103.1 in the 59 games before. It's quite the luxury for OKC to have George, one of the world's best defenders, to step in and take on more primary matchups after losing Roberson. But it's a heavier load on George.
For example, the Thunder played the Wizards twice in the past two weeks, five days apart, once with Roberson and once without. In the first meeting, George guarded All-Star Bradley Beal in the half court 22 times, with Roberson taking him 31 times, according to Second Spectrum. In the second meeting, George had Beal 43 times, nearly three times as much as any other OKC defender.
"None of this is supposed to be easy," George said. "I felt like that eight-game win streak, we were winning because we were hot, we were shooting well, but we were losing sight that our defense wasn't really holding up. We were just outscoring teams. We've got to do both."
The Thunder have slipped in a few areas, but most alarming for Donovan is a three-point increase in opposing 3-point percentage.
"[What] I'm most concerned about that defensively, to be honest, is our 3-point defense," Donovan said. "I'm really, really concerned about that. That's where Andre Roberson is great -- maybe the best I've ever seen -- [at] being able to close down on shooters and get them to bounce it and then also guard them.
"Sometimes it's really hard to do, but we've got to do a better job when we come over to help when the ball gets kicked out ... and I think we've gotten killed at the 3-point line defensively."
The Thunder assembled their team with a mind to compete with the Warriors and Houston Rockets, specifically crafted to match up across the board with them. They have length, athleticism, versatility and firepower. They're one of the few who can play those teams without a specific scheme: Westbrook on Stephen Curry, Roberson on Klay Thompson and George on Kevin Durant.
In the first meeting with the Warriors, a 108-91 thumping of Golden State in OKC, Curry, Thompson and Durant combined for 30 touches on 40 possessions when guarded by Roberson, per Second Spectrum. On those touches, they scored just six points and finished with more turnovers (two) than assists (one).
In the interim, the Thunder are focusing on the details. Internally, they're preaching their system, the sum of their parts connected to fill the gap Roberson leaves. Rebound better. Get back in transition more often. Foul less.
"We've got to get back to our principles, helping one another, being loaded and just having an awareness [that] guys are going to constantly move," George said. "I think defensively our numbers will go back up."
"We were winning because we were hot, we were shooting well, but we were losing sight that our defense wasn't really holding up. We were just outscoring teams."Thunder F Paul George
Still, the Thunder have been active engaging on the trade market, according to league sources, checking for wing additions.
OKC would prefer to not deal Ferguson -- a player they're very high on -- for a veteran rental, and regardless of what lever they pull, they aren't replacing Roberson's skill set or fit. The growing expectation is the Thunder make a move by Thursday's deadline, because there's just too much riding on this season to not.
The chain reaction of Roberson's injury could have a lasting effect on the Thunder if their season goes bust just when it seemed on the verge of finally booming. The uncertainty around the roster is well-documented, but nothing recruits better than success. Roberson wasn't the key to that by any stretch, but he was unquestionably a part of it.
To find their way back on track, the Thunder have some work to do to fill the void.