Sacramento State has joined the Big West Conference as their primary conference, with the intention of moving their football program to FBS. The Big West is primarily made up of fellow California schools, so for most sports this is a good move. The Big Sky Conference had been the best home for their FCS football team but the spread out nature of the conference made it difficult for other sports.
Sac State is taking the space that had been occupied by nearby UC-Davis, which is leaving for the Mountain West in all sports but football, which will remain an affiliate member of the Big Sky Conference. At this time UCD has no announced plans to move football up to FBS.