One thing I like about Porter is his confidence. He's getting a lot of flack for saying that he's the best player in this draft but it's that kind of attitude that is needed on this team.
Porter can believe and be as confident as he wants, but back trouble beginning in his teens is cause for concern. He's been dealing with the injury for a couple years now. He may very well be 'recovered' according to doctors, but I don't believe taking that risk with #2 is worth it. The Kings can't afford to take that chance IMO.
At #7, it might be worth the risk. But at #2 the team needs to go with more of a sure thing --- whomever that may be.