I'd just wait till Sept. Then you don't have to ship another guy back to Iowa for a week or two, and Derrek can just get AB's pinch hitting here and there maybe coming in late to get some defensive work in.
Rookie comes out of no where and pitches a shut out was a better story than veteran returns to his old stomping grounds and gets pounded by his old team ;)
I wonder if they'll bring Miller and Marshall up because i don't think either one will be able to pitch as much as will be needed with the BP the way it is now.