There's really no answer to this. It depends what you want him to be. He could also just learn to miss more bats.
But, as is he probably needs to shave at least 1 BB/9 off of his projections to be a viable starter.
http://www.fangraphs.com/statss.aspx?playerid=7738&position=P
That guy ^ had pretty s***** minor league peripherals too. Lucroy effect? Russ Martin effect for Sanchez hopefully?
If he's going to miss as few bats as Doug Fister though, then he needs to come way down. We don't really know what his SP SwStr% would be, see.