DALLAS (AP) — Conference USA released a football schedule for the 2022 season Tuesday that included 14 teams, saying it will “exhaust all necessary legal actions” to keep Southern Mississippi, Old Dominion and Marshall from leaving the league a year early.

Southern Miss, ODU and Marshall accepted invitations to the Sun Belt during the fall and each announced last week they planned to terminate memberships in C-USA on June 30 to join their new conference.

C-USA says the three schools are contractually obligated to stay put for another year.

“Conference USA intends to conduct the 2022-23 athletic year with the full 14 institution membership intact,” the C-USA board of directors said in a statement. “The C-USA Board of Directors will exhaust all necessary legal actions to ensure all members meet their contractual obligations as defined by and agreed to in the Conference USA Bylaws.”

Six other C-USA schools have announced they are leaving for the American Athletic Conference, but not until 2023.

C-USA has plans to add Liberty, New Mexico State, Jacksonville State and Sam Houston State to rebuild the conference, but those schools are not scheduled to join until 2023.