I suspect that it was a nonexclusive broadcast, where FS1 had rights to show it nationally and NESN (mostly owned by Fenway Sports Group (John Henry's consortium)) had the rights to show it in Red Sox territory while YES (jointly owned by the Yankees and Fox) had rights to show it in Yankees territory (so if you were in Hartford, you'd actually be able to watch the game on three channels, each with different commentary: Red Sox comms on NESN, Yankees comms on YES, and neutral on FS1). I'd expect that if you added up the three channels, you'd get well over a million viewers, but that Fox was willing to pay that much for terrible rights is kind of telling how crazy the sports rights market is right now. Then again, the only reason now to pay $100 or more a month for TV or not record everything and skip the ads is live sports....
thanks.