According to ESPN.com's Royce Young, a Thunder spokesman confirmed Thursday that while "the initial injury is said to be healing well," Roberson "had an irritation from a suture that was creating discomfort that he couldn't play through."
Roberson suffered the injury in January and was ruled out for the remainder of the season following 39 appearances.
And while he only chipped in 5.0 points per game, Roberson's contributions extended well beyond the box score. Namely, he provided lockdown defense on opponents' top perimeter scorers and alleviated some of the pressure on small forward Paul George.
When Roberson sat, though, Oklahoma City allowed a whopping 107.6 points per 100 possessions.
In the meantime, the Thunder will have to try to tread water with the likes of Terrance Ferguson, Alex Abrines and Timothe Luwawu-Cabarrot primed for upticks in usage on the wing.