It isn't unusual (except in KC) for any backup to come in and perform well in his first game since D's don't know what his strengths/weaknesses are and how the gameplan changed. If Kap gets the nod, it'll be interesting to see how he does 2-3 weeks from now. If he isn't playing well, then Harbaugh looks like an idiot for changing.
Seahawks 2012 & Forever. No more waiting on a QB.