Should Pete Carroll have replaced the injured Mark Sanchez with back-up Garrett Green (Shoulda-woulda,...)?

I thought all 4 'SC quarterbacks were potential break-out stars and future starters. If Sanchez goes down, it's Green's trained job to come in AT FULL STRENGTH and run the show. Is Pete showing no confidence in Green (and the other 2 back-ups)? Does this remind anyone about John David being left in a game with a BROKEN HAND instead of having confidence in a back-up named, ummmm, Sanchez? If I recall, USC lost that game too, to the team that just BEAT the team that beat 'SC yesterday.