It is an "if necessary" game - the Yankees had to win last night in order for the game to be played - so "the guide hasn't been updated yet" is my guess. (Are postseason games even subject to blackouts?)
I find it odd that the game is supposed to be on TBS at 6:10 central, but is not listed on the guide.
Using Google, I see it's on live on MLB.TV. At the top of the 4th it's 1-0 Yankees.