Mills's ex-publicist Michele Elyzabeth said she had set up a "little cameo" on the show, but it fell through.
She claimed that while the producer was "keen" on the move, Longoria Parker was "totally against it".
"I reckon they saw the chance to get some headlines for the show. But when the stars discussed it, [Longoria Parker] demanded Heather be dropped from consideration," Elyzabeth remarked.
Meanwhile, Desperate Housewives bosses recently announced that Lily Tomlin has joined the cast of the show.