They have said publicly that he will not be up this season, even in September. They have plenty of options available to be fill-in starters if necessary, Lester (Tavarez), Gabbard, Snyder, Alvarez, Hansack, Pauley, and Runelvys all with major league experience. However if they're up 20+ games in Sept. I don't see why they wouldn't trot him out there for a home start versus a Tampa or Baltimore to see how he handles himself in a no pressure situation.
I may be a bit of a homer, but I love the kid. And I think more of Bowden.