Based on last year, only certain games were shown in HD (I believe the only HD game shown were against the Mets and Red Sox).
Cablevision basically has a stanglehold on the local HD markets in the NYC area (I'm in Bergen County, NJ). I was also hoping to get MSG HD and FSNY HD but its a no go for DTV.
I stand corrected, I forgot that home games were in HD. The above list was the exception where games could be away and still be in HD