The Atlantic 10 Conference, which is losing several of its top basketball programs this summer, will fill one of the vacancies Monday.
George Mason will join the Atlantic 10 as of July, multiple media outlets reported.
The Patriots will end their 28-year affiliation with the Colonial Athletic Conference. George Mason athletics might be best known for the men's basketball team's run to the 2006 Final Four.
Butler and Xavier will leave the A-10 to join the "Catholic 7" as part of the new Big East Conference next season. Temple is joining the football-playing members of the old Big East in a conference that has yet to announce its name. Charlotte is exiting the A-10 to participate in Conference USA.
Five A-10 teams were in the NCAA Tournament this year, and each won at least one game. Only one CAA team, James Madison, was in the field, and it had to win a First Four game just to earn a No. 16 seed. After beating LIU Brooklyn, James Madison lost 83-62 to top-seeded Indiana in the second round.
George Mason's departure from the CAA follows those of Georgia State, which is heading to the Sun Belt Conference, and Old Dominion, which will join Conference USA. Virginia Commonwealth transferred from the CAA to the A-10 for the 2012-13 season.
According to the Washington Post, George Mason turned down an opportunity to join the A-10 last year before reversing course this year.