The American Athletic Conference has received applications from six schools hoping to join the conference, and the AAC is expected to send them each a formal letter by the end of the week detailing the terms of expansion, a source with knowledge of the process told ESPN on Tuesday.

Florida Atlantic, Charlotte, North Texas, UTSA, Rice and UAB have each officially requested to join the AAC, a move that was first reported by Yahoo Sports on Monday. It's the first step in the realignment process, which is expected to move quickly this week after the university presidents and their general counsels have time to review the terms.

The AAC's desire to expand comes after Cincinnati, UCF and Houston decided this fall to eventually join the Big 12. UConn also left after the 2019 season. The addition of six more schools would expand the AAC to a 14-team conference in football and basketball while crippling Conference USA, where all of the schools currently call home.

According to the source, the earliest they could join the conference would be the 2023-24 season, but it depends on what the AAC works out with the schools that are leaving. AAC bylaws require schools to give a 27-month notice before they leave and pay a $10 million buyout fee.

AAC commissioner Mike Aresco told ESPN in mid-September that the league would be willing to negotiate an earlier exit fee to accommodate the departures of UCF, Cincinnati and Houston. If those three schools abided by the bylaws, Aresco said, their exit date would be July 1, 2024.