The three-time All-Star appeared to suffer the injury midway through the second quarter as he rose to pursue an offensive rebound in traffic. Westbrook's hand appeared to make contact with the back of Oklahoma City center Kendrick Perkins as he jumped for the ball.
Immediately after the rebounding scrum, Westbrook flexed his hand in apparent discomfort and then lost the ball out of bounds before exiting the court. On his way to the locker room, Westbrook engaged in a brief exchange with a fan or fans at the Staples Center.
Oklahoma City is already without reigning MVP Kevin Durant, who underwent foot surgery earlier this month. Reggie Jackson, Jeremy Lamb, Anthony Morrow and Mitch McGary are among the other Thunder players who are currently injured. The loss of Westbrook leaves Thunder coach Scott Brooks with only eight healthy players. Reserve point guard Sebastian Telfair will be forced to step up in Westbrook's absence.
After scoring 38 points in a scintillating opening-night effort against the Blazers on Wednesday, Westbrook departed with just two points and four assists in nine minutes against the Clippers.