Irvin's a great speed rush DE playing on non-run downs, and losing a pro-bowl D-lineman is going to affect your rush and your depth.
I only saw parts of the first quarter (it was the last day with my kids for a year, and then I went to the airport) and it seemed as if Quizz channeled his inner Peterson and Turner hooked up a dose of the Juvenation Machine before the game. I saw Sherman being pretty active though. Did he give up any of the TDs?