Longtime political operative and outspoken Donald Trump supporter Roger Stone is fast becoming persona non grata on cable news.

An MSNBC spokeswoman confirmed to the left-wing watchdog group Media Matters this week that Stone had been banned from the network. She wouldn't say why or when the network decided to blacklist Stone, whose involvement in politics dates back to the Nixon administration, but would say only that the network had removed him from their stable of welcomed guests.

Media Matters was the first to notice that MSNBC had ended its relationship with Stone.

But more evidence surfaced when Stone was interviewed for an episode of "With All Due Respect," which airs on both Bloomberg TV and MSNBC. Though Stone's appearance was included in the April 4 Bloomberg TV version of the program, which is hosted by Mark Halperin and John Heilemann, the version that aired on MSNBC one hour later excluded his interview.

MSNBC's Steve Kornacki interrupted his network's version of the program to cut away to Ohio Gov. John Kasich, who was speaking at the time in Huntington, N.Y. The network then cut back to "With All Due Respect" at the moment that Stone's appearance ended. MSNBC even removed Heilemann's reference to the interview, which can be seen in the Bloomberg version of the show.

The longtime political operative was banned from CNN in February over a series of controversial comments he made on social media, including when he called GOP strategist Ana Navarro an "entitled diva B——h" and "borderline retarded."

Stone also said that Navarro reminded him of a "rabid pekinese," "dumber than dog s—t," and referred to CNN political analyst Roland Martin as a "quota hire."

"Look, I've admittedly done and said many controversial things. But, I'm also a veteran of nine Republican presidential campaigns, and I've helped elect three Republican presidents, and I have a unique perspective on the current Republican front-runner. What is her credential? Other than being a Hispanic woman, what is her credential?" he said at the time in an interview with the Daily Caller.

"My problem really is the same, whether it's Roland Martin or Ana Navarro: why do we have people who have no qualification whatsoever to opine on political matters being asked their opinion?" he added. "Ana is a 'Republican strategist?' OK, what campaigns? Who are the people she's elected? Name them. City council, county commission, governor, senator, congressman, president, anybody? And the answer is nobody."

Stone, who served as an adviser to Trump until his abrupt exit from the campaign in August 2015, raised eyebrows this week when he said in a radio interview that he would make public the hotel room numbers of all non-Trump supporting Republican National Convention delegates.

"We're going to have protests, demonstrations. We will disclose the hotels and the room numbers of those delegates who are directly involved in the steal," he said Monday in an interview with Stefan Molyneux on Freedomain Radio, referring to a supposed GOP conspiracy to "steal" the party's nomination from Trump.

Neither Stone nor spokespersons for MSNBC responded to the Washington Examiner's request for comment.