I don't necessarily think he is a bad manager. I don't think he made the wrong call in San Fran considering he had a young arm, an investment and more importantly a person at risk. Would it have been nice to see Ross given the opportunity to at least finish or lose the no-no? Yes but it would've been worse to see him get hurt on pitch 104 or something like that. I don't think he mismanaged that game at all. He did what was best for his club's future and unfortunately the bullpen didn't come through that night.
Last night was a completely different story. Ross was due up second in the bottom of the 5th, having already thrown 95 pitches. Why not pinch hit with Joc Pederson or Adrian Gonzalez, who were both on the bench last night and let your bullpen go to work instead of letting a tired arm with a high pitch count go back out there? The decision came back to bite him as Ross gave up two hits which led to a run and was removed after getting the first out of the inning. It ended up being the difference in the game. Of course there would've been no guarantee, especially with a bullpen that had been used quite a bit the weekend before in Denver, that they would've shut down Miami anyways.
It happens and guys make mistakes. Personally think it was a mistake to not pinch hit for Ross in the 5th, but who knows what went through Roberts's head. I wasn't upset with the way Ross pitched at all, management screws up sometimes and that's alright. Thank god theres 162 games and room for mistakes.