Co-host Tom Bergeron will return when the celebrity dance competition begins its second season next Thursday, Daily Variety reported.
"A decision was made to go in a different direction," an ABC rep said of Canning's firing.
Variety noted Fox TV's "American Idol" underwent a similar fine-tuning between its first and second seasons. Brian Dunkelman, who was co-host of season one with Ryan Seacrest, was nowhere to be found when the show returned for its sophomore season.
Harris will appear weekly on "Dancing" and keep her reporting job at E! News, Variety said.