Brian Williams decided on his own to step aside from his NBC newscast for several days and was under no pressure to do so by network executives, a person familiar with the situation says.

The move on Saturday, developed in consultation with the NBC brass, was not a thinly disguised suspension. In fact, no one, including NBC News President Deborah Turness, suggested that Williams take time off, this person says.

What’s more, according to the source, NBC is not conducting an internal investigation of its anchor, as has been widely reported. The network is engaging in journalistic fact-gathering so it can respond to questions about the crisis created by Williams’ false story about having been in a helicopter in Iraq that was hit by a rocket-propelled grenade. That means there will be no report with a finding on his conduct, this person says.

Williams knows that he needs to address the situation beyond the botched apology this week that made matters worse. And he has a prime forum coming up: An appearance scheduled for Thursday on CBS’s “Late Show” with David Letterman.

Williams is strongly considering keeping the appearance and using it as an opportunity to clear the air and address the lingering questions, the source says, but no final decision has been made.

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Ironically, the anchor will be sitting in the same chair where he told Letterman the false Iraq story in 2013—a clip that has been widely replayed to show that he has repeatedly claimed to have been in the downed Chinook.

No one, including Williams, is minimizing the gravity of the situation. He is said to be embarrassed and very remorseful about the crisis that he created by misrepresenting what happened in Iraq in 2003.

NBC executives have not publicly defended Williams, fueling media speculation that his job may be in jeopardy. But the person familiar with the situation says Williams wanted no such public show of support, fearing it would appear to be the kiss of death.

That’s because NBC management had expressed support for David Gregory before dumping him as moderator of “Meet the Press,” and for Ann Curry before pushing her off the “Today” show.

Williams understands how badly he has damaged the news division. He told colleagues this week that while the Iraq debacle was solely his mistake, he hurt all of them because he is the high-profile face of NBC News.

He also is acutely aware that by saying during his apology that he was in a “following aircraft” behind the chopper that was hit—which was debunked by Stars & Stripes—he prolonged the controversy and made matters worse.

On the central question of why he claimed to have been in the helicopter that was struck by an RPG, Williams is said to believe that he simply succumbed to the sin of exaggeration. Armchair pundits have been analyzing whether he somehow convinced himself that he was a hero by taking enemy fire.

For now, at least, Williams’ job at NBC, where he has been the top-rated network anchor for a decade, appears secure. But that could change if journalists poke more holes in other stories reported by Williams.

For instance, a report in the New Orleans Advocate questioned whether Williams actually saw a dead body floating by his hotel when he was covering Hurricane Katrina in 2005, as he has repeatedly said.

The New Orleans Times Picayune reports Saturday that since the anchor was staying at the Ritz-Carlton in the French Quarter, “it is possible Williams saw floodwater outside the hotel, as water pouring in from failed levees reached that [area]. The Associated Press reported that a news photographer and a law enforcement official said they saw bodies in the area.”

By handing his anchor duties to Lester Holt for a week or so—there is no exact timetable—Williams hopes to minimize the distraction that his credibility problems have created. But whether he can achieve his goal of regaining the audience’s trust depends on how he handles the mounting questions in the days ahead.

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Howard Kurtz is a Fox News analyst and the host of "MediaBuzz" (Sundays 11 a.m. and 5 p.m. ET). He is the author of five books and is based in Washington. Follow him at @HowardKurtz. Click here for more information on Howard Kurtz.