Update on USC safety Kevin Ellison

Posted by ESPN.com's Ted Miller

USC safety Kevin Ellison tore cartilage in his right knee during Thursday's practice and will have arthroscopic surgery early next week, according to a release from the sports information office.

He will be out for two to four weeks. Will Harris will start for him Saturday against Washington.

Ellison, a senior, has been the most consistent performer on the nation's best defense this season.