TBS HD and MLB and NBA
From what I know from a pretty good programing source, I Expect TBS HD to launch in September, though I have heard there is some doubt about that related to technical issues.
Also:
If TBS is not available in HD in a certain percentage of households by Oct. 1, then MLB HD playoffs will be in TNT HD.
If TBS HD is available by Oct. 1, then Dish will have it because they won't want to miss the playoffs. And I don't think TBS HD costs Dish any extra money.
If TBS HD is not available during the NBA season, the games on TBS will move to TNT HD.
So:
If I were a Dish HD subscriber (and I am) I would not worry about missing HD MLB playoff games or NBA games.
There are plenty of other things to worry about.