Now it's been revealed what the studio's reasoning behind the unusual casting change was: Whitmire's "unacceptable business conduct."
Regarding the business conduct problem, Steve Whitmire's communication style was described as "overly hostile and unproductive," and his negotiation tactics also delayed production numerous times. This "unprofessional behavior" had supposedly been going on for a number of years, and because Whitmire did not address Disney's feedback to him, the studio finally decided to fire him last October.
Steve Whitmire went into more detail on the behind-the-scenes drama will providing his side of the story to THR, saying that one of the main reasons for his dismissal was because of the short-lived Muppets TV series that aired from 2015 to 2016. Whitmire, who had been performing for The Muppets since 1978, stated that while the show was airing, states that Disney felt that he had been "disrespectful" during the show's run because of his character issues with Kermit the Frog in that project.Read more at HollywoodReporter