Ernesto Martinez should be a good defender with his size and flexibility (he can do the splits) but it just hasn't translated to good defense. His bat has been pretty awful this season as well. Hall and Metzinger are both currently seeing more time than him at 1B right now.
I really hope the Campbell promotion was real. With Hiura injured, the Sounds should have no issues find Campbell plenty of playing time between 1B, 2B, LF, DH. Plus he's earned the promotion having a 117 wRC+ in 366 PA in AA.