"I think the thing for all of our alumni and supporters to realize is that passion is very important ... and they can take pride in our football program as we move forward," he said.

The decision is expected to have significant impacts on the future of the Big Sky, which now has 14 football-playing members with the addition. Big Sky Conference Commissioner Doug Fullerton has said in the past that adding a 14th school could key a realignment of the conference, possibly into two divisions.

"We think that, given Idaho’s DNA of excellence, they will make our football programs better, and our football product better," Fullerton said in a release from the Big Sky on Thursday.

Even at 13 schools, which include football-only members Cal Poly and UC Davis, the Big Sky is the largest FCS conference in the country.

Idaho must shed 22 scholarships -- dropping from 85 to 63 -- during the move to the FCS. Should Idaho remain above the limit come 2018, the school would be ineligible for postseason play.

Petrino, Idaho’s fourth-year coach, said the Vandals are committed to reaching eligibility for the FCS playoffs right away.