(AP) - San Diego State is staying in the Mountain West and backing out on the Big East - just as Boise State did last month. University President Elliot Hirshman said Tuesday that the school is pleased to be continuing as a full member of the Mountain West Conference. San Diego State, a founding member, had committed to join the Big East for football only, with Boise State, starting next season. San Diego State's other teams were going to compete in the Big West. But recent defections from the Big East caused Boise State to reconsider and strike a deal to stay in the Mountain West. Without a western partner, San Diego State retreated, too. Unlike Boise State, San Diego State is not on the hook for an exit fee, because Boise State left first. San Diego State becomes the third school in the last 16 months to leave the Big East before ever actually joining. TCU did the same, reneging on a commitment to join the league in 2012 and instead accepting an invite to join the Big 12. However, SDSU must pay a $1.5 million exit fee to the Big West, which was where its men's basketball team was headed next season before Tuesday's decision. That money will be defrayed by an estimated $2.5 million year-end distribution from the Mountain West. "After substantial discussion and consideration of a broad range of factors, San Diego State University will be continuing as a full member of the Mountain West Conference in July 2013," Hirshman said in a statement. We have the deepest respect for our colleagues in the Mountain West, Big East and Big West conferences with whom we have worked collaboratively during the period of conference realignment. We are optimistic about the future of San Diego State University's athletic programs and the prospect of building on our university's rich tradition of intercollegiate athletics. The move leaves the Big East with only 10 football members for the forthcoming season, instead of the 12 it had planned to have. It also scraps plans to hold a conference title game, and will force the league office to come up with a new schedule. In early December, it had released a schedule with San Diego State and Boise State in a new western division. The conference has 10 football members for 2013, but two of those - Louisville and Rutgers - are looking to leave by 2014. Louisville is headed to the Atlantic Coast Conference and Rutgers to the Big Ten, though exactly when those moves will take place is still to be determined. Those departures, along with the seven non-FBS football members breaking away from the Big East, and the conference's inability to land a TV deal because of all the instability, caused Boise State to change course and return to the Mountain West. Now the Mountain West will go into next season with 12 members, a restructured television contract with CBS Sports Network that allows the league to make extra money by selling some games, including Boise State home games, to other networks, and it plans to play a football championship game.