The development comes a week after the Lifetime movie "Imperfect Justice" started shooting, the report said Wednesday.
"Holly moved on and they recast the role," a source close to the production told the celebrity magazine. "This is one of those decisions that happens all the time. Holly was good and very talented; it just didn't work."
Anthony was acquitted in July 2011 of murdering Caylee in 2008. The child's skeleton was found in a wooded area near Anthony's home several months after Anthony reported she had been kidnapped, a claim she later recanted.
The cause of Caylee's death was not determined due to the condition of her remains. No one else has been arrested in the case.