I think it's safe to proceed with caution and consider him a starting fantasy QB. That means if you roll with him as a starter then it is a no brainer that you need to have a very good QB2.
That said, I think his days as a top notch, elite, break the bank for QB are over. Or at least he's not proven that.
To be fair, he has been a solid top notch QB when he was playing. At the time he had a terrible oline and still showed over the top talent. That line is much better this year, even if only just middle of the road. I not only think that noone on this site knows what he will be health wise come the regular season, I think his own coaches don't know. Possibly even Luck and his doctor don't know what to expect.
I'm going to take a chance on him if he get's through preseason ok. But like others have mentioned before, grab a decent backup.