The team confirmed Sunday that Dellavedova sprained his medial collateral ligament during the fourth quarter of Cleveland's loss in Portland on Tuesday. Dellavedova, one of the team's best on-ball defenders, has missed the Cavs' past two games and the team said he could be sidelined another six weeks.
The Australian gives the Cavs energy off the bench and the second-year guard has become one of Cleveland's most popular players.
Also, the Cavs said guard Dion Waiters suffered a bruised lower back during the second quarter of Friday's win at Denver. Waiters is listed as questionable for Monday night's home game with New Orleans.
Waiters was in Cleveland's starting lineup to begin the season, but has been replaced by veteran Shawn Marion.
ESPN.com's Dave McMenamin and The Associated Press contributed to this report.