Cleveland Cavaliers center Anderson Varejao will undergo knee surgery on Thursday and miss six to eight weeks, the team announced Wednesday. Varejao was hurt Dec. 18 in a game against Toronto. The injury was believed to be a bruise that might keep him out for a few weeks, but it was slow to heal. Further examination revealed a small tear in the muscle in his right thigh that connects to the knee, which caused additional complications. The Cavs sought a second opinion from Dr. J. Richard Steadman in Vail, Colo., who confirmed the need for surgery. Before the injury, Varejao was leading the NBA in rebounding at 14.4 per game and also averaging 14.1 points. "Smh man, worst news I've heard all day, #getwellandy," Cavaliers guard Kyrie Irving tweeted. Varejao has proved injury prone during his career, missing 92 games in two of the past three seasons with a torn foot ligament and broken wrist.