Andersen suffered a noncontact injury, and an MRI confirmed the tear, the Cavs said.
Andersen is the team's third-string center, but the Cavs used him when their opponents went with bigger lineups, because backup center Channing Frye is undersized during some games.
The injury presents another problem for the Cavs, who have looked for ways to trade Mo Williams?to clear his salary off the books. Williams had knee surgery before the season and did not report to camp, but he is still on the team's roster.
The Cavs, who have the league's highest payroll,?will have the same problem with Andersen, who has a guaranteed contract.
Cutting Andersen to open a roster spot would cost the team roughly $4 million in luxury taxes alone, and a new player could potentially add another $4 million in salary and tax.
Andersen played in 12 games this season, averaging 2.3 points and 2.6 rebounds.