This is a very open question, what are you looking for? Value of the network? No idea, check Forbes, but that is unlikely to give you anything useful. Value added to the baseball team? That's discretionary to ownership and likely not public information.
EDIT: However, Forbes has speculated that YES adds as much as $400M in revenues to the Yankees baseball operations. I fully admit, I do not expect MASN to add nearly that much value, but a reasonable fraction of that, even if you cut it in half (because of the Orioles), is nothing to ignore.