That's a fair point, I forgot about the salary cap.Do not extend him now! He's terrrific and should continue to develop there. But you have a salary cap and a QB earning near the minimum (and only 1/2 way thru contract). He can make extra bucks thru marketing. You do not screw up your cap when there is no reason to do so - this can be handled after next year or early in his 4th year. The worst thing SB teams do is to start throwing money around to guys w/o planning ahead and remembering what got them to the final.
My point was they should look to extend him to keep him out of free agency. If they can afford to wait a year, so be it. From what he's done the first two years, I believe he's a franchise QB, and you don't pass on franchise QBs to save money. You can fill other pieces through the draft and free agency.