Both had been rumored to be included in the studio’s DC superhero tentpole.
Eisenberg had said previously that he would appear in “Justice League,” which opens Nov. 17, 2017. He played the villain in “Batman v Superman: Dawn of Justice.”
In “Justice League,” Nielsen will be reprising her role from the upcoming “Wonder Woman” stand-alone film, which opens in June and stars Gal Gadot.
Warner Bros. had announced in June that the cast would feature Ben Affleck, Henry Cavill, Gal Gadot, Jason Momoa, Ezra Miller and Ray Fisher. Zack Snyder began shooting “Justice League” in April from a script by Chris Terrio with Amy Adams, Amber Heard, Jeremy Irons, J. K. Simmons and Willem Dafoe also starring.
“Batman v Superman,” starring Affleck as Batman and Henry Cavill as Superman, turned out to be mildly disappointing for Warner Bros. with worldwide grosses hitting $870 million. Snyder directed from Terrio’s script, which introduced Gadot as Wonder Woman, Momoa as Aquaman and Miller as The Flash.
A trailer for “Justice League” surprised fans at this past year’s San Diego Comic Con. Based on early footage, the film may try to play up a lighter tone to offset criticism that “Batman v Superman” took itself too seriously.