Assuming he has decent fielding behind him in a neutral park, I'd expect him to have a WHIP around 1.45-1.55 and an ERA around 4.5. He'll be fine as a 4.
Past history. You took over a team built to win a WS during the season. You managed to make the playoffs before screwing them up. Now you've had almost a full season plus the pre-season to put your stamp on the team. That dooms them to 90 losses, more or less.