Oklahoma Gov. Kevin Stitt is currently sorting through a group of potential candidates as he settles on who he will nominate to replace Sen. Markwayne Mullin.

According to a report from News9 in Oklahoma City, Stitt is considering five candidates as his choice to replace Mullin, if the incumbent senator is confirmed to be the next Secretary of Homeland Security. Those under consideration by Stitt include former Oklahoma Republican Chairman Nathan Dahm; Stitt’s chief operating officer, David Ostrowe; former Oklahoma Attorney General John O’Connor; Stitt advisor Dustin Hilliary; and oil and gas executive Harold Hamm.

Under a law passed by the Oklahoma Legislature, whoever is appointed to the seat must sign a nonbinding pledge not to seek a full term in office.

As for who might run in the special election for the seat, Stitt himself is considered a likely candidate, while U.S. Reps. Kevin Hern and Stephanie Bice are also reportedly weighing their own bids.