CLEVELAND — Cavaliers center Zydrunas Ilgauskas could miss up to a month after suffering a small fracture when he twisted his left ankle last month.

Ilgauskas sprained his ankle during a Dec. 10 game at Philadelphia, when he tried to block former teammate Donyell Marshall's shot and landed on the Sixers forward's foot. Tests at the time showed only a sprain and Ilgauskas returned after missing just three games.

But he has been bothered by pain and stiffness since returning, and an MRI taken Friday revealed that Ilgauskas, who missed two full seasons earlier in his career with foot problems, chipped the talus bone in his ankle.

The 7-foot-3 Ilgauskas said he's likely to be "out three to four weeks, but we really don't know."

The Cavaliers third leading scorer at 13.8 points per game, Ilgauskas said the pins and screws in his foot from a restructuring operation were not affected by the injury.

"One good thing is that it's not related to the foot problems that I have," he said. "It's in the ankle. If anything, the MRI showed that all the previous foot surgeries, everything looks beautiful and all the bones are healed. That was the positive."

The Cavaliers' ball movement and offensive production slipped while Ilgauskas was out of the lineup. Despite his size, he's one of the club's best outside shooters and has dropped seven 3-pointers already this season after making just five in his first 10 years in the NBA.

Anderson Varejao replaced Ilgauskas in the starting lineup for Friday night's game against Chicago. The Cavs came in as the NBA's only unbeaten team at home with a 16-game winning streak on their home floor, and at 26-5 are off to the best start in franchise history.

"It's never a good time to do it," Ilgauskas said. "But it's better now that during the playoffs."