For those of us who bought the MLB.TV single team option, we did not get to see last night's great game because Root did not broadcast the game.
I called MLB today and got the scoop. While if you bought the single team option you only get the Pittsburgh feed. However MLB will temporarily upgrade you to premium for a few days so you can use the other team's feed in either the case where the Pittsburgh feed is down or is not being provided (like last night).
They said to just call MLB (866-800-1275, option 1). explain the situation, and they will handle it. If the person you are talking to doesn't know to do this (like the person I talked to last night), just ask for the supervisor.
This sounds fine to me, but I wish I had know it last night!