Perry A. Farrell of the Detroit Free Press reports: Pistons center Ben Wallace is out indefinitely and could miss more time than expected.

Wallace was walking very gingerly before the Pistons game against Chicago and only said that the knee felt the same as the day before.

Wallace sprained his medial collateral ligament in his left knee last Sunday.

"In his absence, we're going to have to become a conscientious defensive team in a couple of areas," coach Rick Carlisle said. "We're going to have to protect the painted area with bodies more so than just depending on him to erase shots. And we're going to have to be a five-man rebounding team on the defensive boards. He's gobbled up so many rebounds over the last two years that sometimes you just expect him to go ahead and get them. We can't be in that situation now. We have to make sure we get the ball."