BYU, Houston, UCF and Cincinnati are planning to submit applications next week to join the Big 12, sources confirmed to ESPN on Friday.
The schools could be approved for admission as early as a Sept. 10 meeting of Big 12 presidents, according to Sports Illustrated, which first reported the story.
"Things are moving very quickly," one source told ESPN on Friday. "There's obvious momentum to get votes to the board."
American Athletic Conference bylaws require schools to give a 27-month notice before they leave and pay a $10 million buyout fee.