He's getting paid big league money currently, too....Not the major part of his salary, but still quite a bit more than a rookie contract/the major league minimum.
You have to give him more time against big league pitching, something that's simply not replicable in AAA. It's not like we any better options right now either, especially with Hoskins likely to go on the IL. He's already shown one major sign of adjustment as his K% has dovetailed to 10% over the last few weeks. Now, he's gotta work to better counts and start swinging at drivable pitches and driving the ball. And he'll probably have until Mitchell returns to do so.