A few tidbids:
-Baseball teams transact based on revenue multiples. The multiples are not derived as much from profitability as they are from lease terms, stadium economics, market demographics, sponsorship roll, and buyer/seller motivation. Numerous adjustments must be made. But if you do it well, you can come up with a reasonably tight range. Also, multiples are being skewed upwards by the value of MLBAM, which each team owns 1/30th of but aren't included in their revenue results.
-You don't necessarily have to pay to set up a regional sports network. Partner with a cable company and they'll pay you a significant signing bonus and give you an equity interest (along with your rights fees). But that's more for big-market teams. Teams in small markets are forced to accept rights fees only.
-Forbes' data is bad. Having seen the real data, their "best estimate" data is off by a large amount for some teams. Also, I'm unsure if they make any sort of adjustments for the structure of the transaction (asset vs. stock deal and the associated tax consequences of each).