Here is one of those things that fascinates me. The baseball quiz show, Baseball IQ, is currently blacked out on MLBNetwork. A game show is blacked out! I was tuning in to check on the Mets/Padres game anyway because the scoreguide said it was on MLB (it is actually on the alternate channel, though not listed in the guide), so I'm not upset about missing the game show, but that is a new height of strangeness in blackouts.
You get one and only one feed of the MLB channel. That could be the main channel on 213 or the alternate on 214/214-1. If 214 was live, then 213 is blacked out, no matter what is on. The scoreguide was wrong. It is sometimes wrong on MLB alternates as it is also often wrong on NBCSports alternates.
Right now, I am getting Mets/Padres on 214 and blacked out on 213. I cannot say what is on 213 but I am assuming it is the Tigers and Twins.
The Mets game started at 1 pm and the Tigers at 2 pm (ET). So, there is an hour where 213 would be blacked out without a live game if you are getting the Mets game.
The key is that you NEVER get both channels of MLB, no matter what is on.