Roberson's departure leaves the Thunder with just eight healthy players available against the Brooklyn Nets.
The shooting guard already dealt with a sprained ankle in late October, which caused him to miss a practice. Through three games this season, he's averaging 7.4 points and 7.0 rebounds.
A defensive specialist, last season Roberson averaged 1.9 points and 2.4 rebounds in 40 games, including 16 starts. The 22-year-old was a first-round draft pick in 2013.
Oklahoma City is already without forward Kevin Durant, who underwent surgery last month for a fracture in his foot, and point guard Russell Westbrook, who is out at least one month after having surgery on a broken hand.
- Molly Geary