Westbrook fractured his hand on Oct. 30 and later underwent surgery. He was expected to be out for four to six weeks.
Westbrook played in every game in each of his first five seasons, but was limited to just 46 games last season with a knee injury.
Earlier this month, the NBA granted the Thunder a hardship exemption to add a player to its roster because of its long list of injured players which also includes Perry Jones III and rookie Mitch McGary.
The Thunder waived reserve point guard Sebastian Telfair on Wednesday.
- Dan Gartland