A postgame MRI confirmed the injury, the team announced after the game.
The injury happened late in the first quarter when Freeland's knee buckled underneath him, and he had to be helped off the court.
The Blazers depend on the 6-foot-11 Freeland to spell starting center Robin Lopez. Freeland is averaging 3.3 points, 3.9 rebounds and 0.4 blocks in 13.9 minutes a game.
Portland was already without guard Mo Williams, who had just returned from attending to a family matter. It was hoped that Williams could travel with the team to face the Clippers on Wednesday night.
The Associated Press contributed to this report.