To me, Masterson was a low risk low reward guy. He was unproductive right out of the gate so he should have been dumped the second he came back from the DL.
Masterson has a major league contract. He was only in AAA to rehab an injury. You can't generally just stash guys with major league contracts in AAA just for shits and giggles without DFAing and such.
It looks like there's confusion as where the cut off man will be. That's coaching.
Hankey may have bobbled a ball, but Masterson would've let the runner score right after anyway.