I would definitely call up Blankenhorn. Of course, there's no guarantee that he will be a good hitter straight away but then look at Marwin's and Ehire's stats. He doesn't even need to be very good, he just has to hit over .200 to be no worse than either of them. In short, the Twins can only win if they call him up. Worst case would be that he is no improvement, and with a little bit of luck he will be better. And if he really doesn't manage to top Marwin's .204 AVG you can still send him down again.