The Lakers announced the results of Blake's ultrasound exam on Monday. He left Los Angeles' 103-90 victory over Sacramento on Sunday night in the first half.
Blake is averaging 5.1 points, 3.4 assists and 2.4 rebounds in seven games this season, hitting just 35.3 percent of his shots.
He has started the Lakers' past five games in place of two-time NBA MVP Steve Nash, who is sidelined at least until this weekend with a small fracture in his leg.
The Lakers' remaining point guards are Darius Morris and veteran Chris Duhon. Morris is averaging 6.6 points and 2.2 rebounds per game.