Is it MLB or Fox?
I can’t find any cites either way and I have now heard both.
The playoffs are scheduled by MLB in conjunction with FOX and ESPN. MLB officially has the last word, but they rarely do it.
Selig has said that he would like to have weekend day games in the World Series, but Fox doesn’t want any. Fox feels that Saturday games would lose out to college football and on Sundays, there’s this sport called the NFL.
MLB baseball can schedule their games whenever they want, but the networks provide a majority of their revenue. So they listen very carefully to any suggestions the networks may have.