In other words it was the manager's fault. But managers are always looking at a bigger picture than we are, and know more about availability and match-ups than we do. Certain relievers weren't available and others only pitch with a lead. But mostly I think Girardi wasn't trying to do everything possible to win the game, we already took the series and have three more games in a 30-hour span coming up, including a bullpen start, that may already have some guys down. Using Hembree there was at best an audition and at worst a white flag to save other arms for the next batch of games.
If Howard or Arrieta make it back for the playoffs is when it will get interesting, Joe's like almost any other manager, he still values experience and saw Hembree pitch a lot in the AL East.
You probably don't keep both Hale and Hembree, on the active, do you keep Brogdon? They released the playoff pool today, but that is basically just your 40-man, even Alvarez is on that to keep him eligible when he's activated (which can't even be until the NLDS).