Roberson had to be taken off the court on a stretcher during the Thunder's Saturday night victory over the Detroit Pistons. He had been loading up to attempt an alley-oop finish when his leg gave out and he fell onto his backside.
Several of Roberson's current and former teammates wished him well in the wake of the injury:
He had previously missed eight games this season with patellar tendinitis in the left knee he injured on Saturday night, according to Michael Rothstein of ESPN.com.
Roberson, 26, was averaging 5.0 points and 4.7 rebounds per game, shooting 53.7 percent from the field but just 22.2 percent from three and 31.6 percent from the free-throw line. His biggest contributions come on the defensive end, however, where he's established himself as one of the best perimeter stoppers in the NBA.
"He's certainly a huge loss," head coach Billy Donovan said on Saturday night, per Rothstein. "Everyone's been able to see that since he's kinda come back to us and what he's been able to do defensively. And he's found a way to be, offensively, a really effective player for us."
Roberson's defensive impact is huge. As Rothstein noted, the Thunder have given up 95.9 points per 100 possessions over 539 minutes when Roberson plays with Russell Westbrook, Paul George, Carmelo Anthony and Steven Adams. Take Roberson out of that group, however, and they've given up 114.5 points per 100 possessions in 402 minutes.
"A lot changes," Westbrook noted on Saturday. "A lot of things that's not seen on the court, a lot of things not seen in the stat sheet—and that's a huge part. Like I've always said, he's a huge part of our team's success. And obviously, with him going down, we've got to be able to figure out and make up for the things he brings to the game defensively and offensively."
With Roberson out for the year, rookie Terrance Ferguson and sophomore Alex Abrines are likely to see their minutes increase significantly.
The Thunder could also seek to add another wing via free agency or a trade. Bobby Marks of ESPN.com reported that the team has an open roster spot and and two trade exceptions for $2.55 million and $1.49 million, though they "cannot trade a first-round pick until at the earliest 2024" based on a number of obligations made in previous deals.