TBS has done quite well since they dropped Atlanta Braves baseball. Just look at the ratings their Primetime Lineup gets.
My guess is that WGN is trying to do something similar and may look at creating some original programming. The bottom line is that baseball ratings have been tanking and it won't take much to replace the number of viewers the Cubs/Sox were bringing in.
"This is an individual sport, under a team concept. No one can swing for you. No one can pitch for you. There's nothing wrong with talking about numbers."