After months of rumors, Current announced abruptly this afternoon that it had replaced Keith Olbermann with Eliot Spitzer in the 8 p.m. weeknight time slot. Read their statement here . A source told Politico that Current was claiming that the former MSNBC host had "sabotaged" the network, and was absent from the show far too often, and so was in breach of contract. More from The New York Times here. 
UPDATE at 9 p.m. Friday: David Letterman's Twitter feed for his "Late Show" reveals that Olbermann "will join Dave on the @Late_Show  on Tuesday, April 3rd to talk about his departure from Current TV." Also, Olberamann on Twitter tonight is tweeting baseball....SATURDAY: Opinion piece  at The Hollywood Reporter by a Keith buddy. And Olbermann says he's now busy--with two fantasy baseball league drafts....David Carr at NYT weighs in, under headline calling Olbermann "machine gun for hire."
Olbermann, who left MSNBC just 14 months ago, on Friday responded with a note to viewers , promising a lawsuit, blasting his bosses (including Al Gore), apologizing to viewers and admitting he had made a "foolish" mistake in taking on this challenge with the little-seen network to start with. He had an equity stake in the network but long complained about technical problems on the set, including lights going out on several occasions. Last fall he provided some of the strongest, and most frequent, coverage of the early weeks of Occupy Wall Street.
Here is his note (which he sent out in a series of tweets) in its entirety:
I'd like to apologize to my viewers and my staff for the failure of Current TV.
Editorially, Countdown had never been better. But for more than a year I have been imploring Al Gore and Joel Hyatt to resolve our issues internally, while I've been not publicizing my complaints, and keeping the show alive for the sake of its loyal viewers and even more loyal staff. Nevertheless, Mr. Gore and Mr. Hyatt, instead of abiding by their promises and obligations and investing in a quality news program, finally thought it was more economical to try to get out of my contract.
It goes almost without saying that the claims against me implied in Current's statement are untrue and will be proved so in the legal actions I will be filing against them presently. To understand Mr. Hyatt’s “values of respect, openness, collegiality and loyalty,” I encourage you to read of a previous occasion Mr. Hyatt found himself in court for having unjustly fired an employee. That employee’s name was Clarence B. Cain. http://nyti.ms/HueZsa 
In due course, the truth of the ethics of Mr. Gore and Mr. Hyatt will come out. For now, it is important only to again acknowledge that joining them was a sincere and well-intentioned gesture on my part, but in retrospect a foolish one. That lack of judgment is mine and mine alone, and I apologize again for it.
Greg Mitchell's new book, with Kevin Gosztola, is just out this week: "Truth and Consequences: The U.S. vs. Bradley Manning. "