The move sets up a possible rematch between Mr. Jones, the last Democrat to win statewide office in Alabama, and Tommy Tuberville, the Republican who ousted him from the Senate in 2020.
Still the favorites, Republicans have grown nervous about a House special election that could show whether the political environment continues to shift leftward.
Aftyn Behn, a Democrat, is facing off against Matt Van Epps, a Republican, in a House special election for a district in Tennessee that President Trump won by more than 22 percentage points last year.