First of all Kalil went to the pro-bowl last year so stop with all the "we don't have a center who can execute the shotgun". We use the shotgun in the hurry up and 2 minute offense every game with no problem. Clausen funbling a few snaps from our backup center has no bearing on the starters.
Secondly we don't use the shotgun as much as other teams because we use more play action passing which usually involves the quarterback lining up in a running formation and faking the run before dropping back to pass.
Finally, this Saturday will tell the most. Tennessee will come on the blitz like Baltimore and New York did. We should be prepared for it on offense. Hopefully we will make the hot read changes and will employ some screens and other dump passes to swing the pressure to our favor.