Kleiza had microfracture surgery Wednesday in Vail, Colo., the team said in a statement Thursday. Kleiza had missed Toronto's past seven games.
The former Missouri star averaged 11.2 points and 4.5 rebounds in 39 games this season. He had six games of 20 or more points, including a season-best 26 on Dec. 10 against Denver, which he matched nine days later against the Los Angeles Lakers.
Kleiza signed an $18.8 million, four-year deal with Toronto in July.