Opponents of the SAG-AFTRA merger will file a motion for a preliminary injunction Monday, setting the stage for a possible March 26 hearing in federal court — four days before the merger votes are to be tabulated.

But SAG is expected to file a motion to dismiss the case as early as Friday, according to a source familiar with the situation, alleging that the plaintiffs have failed to state a cause of action.

Plaintiffs’ attorney David Casselman of Wasserman, Comden, Casselman & Esensten told Variety that the suit is aimed to ensure that the Screen Actors Guild adheres to its own rules. “The complaint isn’t meant to subvert the process.”

The Screen Actors Guild and the American Federation of Television and Radio Artists are scheduled to mail out ballots Monday to 120,000 SAG members and 70,000 AFTRA members. To be approved, the merger must receive at least 60% of the votes from each union.

The opponents filed suit Wednesday, alleging that SAG is attempting to merge with AFTRA “without conducting the necessary due diligence.” U.S. District Court Judge James Otero has been assigned to the case.

SAG vowed to “vigorously” fight the action, calling it “a clear attempt at circumventing the will of the membership” and emphasized that it has held more than 50 informational meetings around the country in the run-up to the merger referendum.

About 40 opponents picketed Thursday at SAG headquarters — the third such event in the past two weeks.

Former SAG president Alan Rosenberg, who’s a plaintiff in the suit, attended along with former board members Renee Aubry, Mark Carlton, Frances Fisher and France Nguyen.