it's possible that zito's value went up after the season ended. on a draft i think people will take a chance on him cuz they figure he can't be as bad as he was last year. in bad i mean compared to his cy young year, cuz, i might be alone on this one, i don't think he pitched that poorly last season.
i don't think you should rely on him as the #1 SP on your team and i'd also be worried if he was my #2.
i think Cornbread Maxwell gave a good advice that you should let someone else draft him and then trade for him if he has a slow start, but don't overpay for him, people tend to overvalue players who have won awards.