sentences:  Backup quarterback Patrick Cowan also suffered a knee injury but returned for two more games before suffering a collapsed lung against Arizona.Coach Karl Dorrell was fired following the loss in the 77th UCLA–USC rivalry football game, the final regular season game for the Bruins.Defensive coordinator DeWayne Walker became the interim coach for the 2007 Las Vegas Bowl, in which the Bruins lost to BYU, 17–16.