I spent the better part of two decades repairing Snappers. There is virtually none of the spindle exposed, so bending one is highly unusual. You say the blade runs good inside the deck, which pretty much says it's not bent. Since you don't elaborate on why you think it is "shot", I can only speculate that the symptom is a vibration. If that is the case, check the belt and pulleys. A bad spot burned into the belt, a bent pulley, something lodged in a pulley, will cause lots of vibration. Without better info, that's what I got.