I think it's fair to worry until he faces some snow / rain / cold / ice and shows he can handle it. I think Trent's a really great pickup, and I'm keeping my fingers crossed, but to all those proclaiming "Franchise QB!" with visions of sugarplums dancing in their heads, just think - Carson Palmer. Even one season does not a franchise QB make.
Again, not trying to be negative, just trying to temper some of the enthusiasm on the board.