I have always thought that having any part of the playoffs on cable tv is bad for creating interest. The World Series should be the final act in the drama of the baseball championship tournament. However, you are asking a small but significant portion of the population to drop in at the end of the show after all the character development has taken place. Even within the group of cable holders, TBS is not a primary choice for those casually interested in sports. The early round games take an affirmative effort on the part of viewers to find which is an impediment to maximizing viewing.
If I were MLB, I would be willing to take a little bit of hit in profits to get these games on CBS, NBC or ABC with Fox running a distant 4th and ESPN/MLBTV being used for complimentary coverage.