NCAA only allows 12 games for FCS when there are 14 Saturdays from Week 1 to week before Thanksgiving. In 2015, Labor Day is on Sept 7. Only 13 Saturdays from Labor Day weekend to the week before Thanksgiving, as Thanksgiving is on Nov 26th, and that will be first week of playoffs.
NCAA is allowing an FCS game the weekend before regular season starts, and having the game on ESPN. Game is called "FCS Kickoff" and it started this year with Sam Houston at Eastern Washington... In 2015, it is going to be NDSU at Montana on Aug 29th.