Eugene, OR -- (Sports Network) - University of Oregon sophomore quarterback Nate Costa is expected to miss at least eight-to-10 weeks after he undergoes surgery to repair damaged cartilage in his left knee.

Costa also tore ligaments in the same knee last October, but was expected to compete for the starting QB position with redshirt sophomore Justin Roper for the Ducks' season opener on Saturday against Washington.

The date of surgery, which will also evaluate the anterior cruciate ligament and medial collateral ligament, has yet to be determined.