Hosts Hoda Kotb, left, and Savannah Guthrie work on the set of the “Today” show Wednesday, Nov. 29, 2017, in New York, after NBC News fired host Matt Lauer. NBC News announced Wednesday that Lauer was fired for “inappropriate sexual behavior.” (AP Photo/Craig Ruttle)

After years of morning TV dominance, the face of the “Today” show for two decades is suddenly gone at a time when NBC’s crown jewel is locked in a fierce ratings battle with ABC’s “Good Morning America.” NBC was also preparing for the high-profile Winter Olympics in February, when Lauer was likely to anchor much of the network’s coverage.

Now, the Comcast Corp.-owned network quickly must find a replacement for its biggest star, an especially delicate move in the business of morning television, where viewers often see the hosts as family of sorts.

“Morning shows are all about easing the audience into their day,” said Jon Klein, a former president of CNN in the U.S. “A good smooth chemistry among the team members is essential. Now the chemistry is disrupted.”

NBC fired the 59-year-old Lauer on Wednesday, saying it was informed about inappropriate sexual behavior him after a colleague complained.

“There are no words to express my sorrow and regret for the pain I have caused others by words and actions,” Lauer said in a statement on Thursday. “To the people I have hurt, I am truly sorry.”

Lauer said he realized the “the depth of the damage and disappointment” but added “some of what is being said about me is untrue or mischaracterized.” Still, “there is enough truth in these stories to make me feel embarrassed and ashamed.”

He added that his “full-time job” is now “repairing the damage.”

The stakes are high for NBC. “Today” has been the top-rated morning show among 25- to 54-year-olds, the key demographic for advertisers, for much of the past two years, but its audience is starting to decline. Total viewership for the program is down 10 percent year to date, according to Nielsen, and it has been eclipsed by ABC’s “Good Morning America” among audiences of all ages. NBC has tried to boost ratings by adding former Fox News host Megyn Kelly to its third hour, but her viewership has been lackluster.

Those ratings still translate into a lot of money. “Today” generated about $508 million in advertising revenue last year, according to the research firm Kantar Media. That sum may seem tiny for Comcast, a cable and entertainment conglomerate that generated about $80 billion in revenue last year. But the production costs of programming like “Today” — which consists mostly of four hours of people chatting on a set — help produce fat profits. And the show is still immensely valuable to a network at a time when TV viewership is in decline.

“The franchise is hugely important to NBC and Comcast,” Klein said. “It throws off a lot of revenue and profit so they have to treat it carefully.”

NBC and Comcast will also have to contend with questions about how they handled Lauer’s behavior as details of the allegations trickle out. Variety reported Wednesday that the anchor had a button on his desk that could lock his office door, allowing him to initiate contact with women without being disturbed. The publication, citing interviews with dozens of unnamed people who worked with him, said Lauer’s frank sexual talk and fixations on young female coworkers were widely known on the “Today” set.

“We can say unequivocally, that, prior to Monday night, current NBC News management was never made aware of any complaints about Matt Lauer’s conduct,” the network said in a statement.

It’s unclear how much damage the loss of a single personality can inflict on an institution like “Today.” The program has been on the air since 1952, and it’s endured plenty of controversial moments, from the unceremonious exit of Jane Pauley in 1989 to Ann Curry’s tearful goodbye in 2012 — an awkward moment widely attributed to her tense relationship with Lauer.

“Some years ago, the conventional wisdom was this is a cataclysmic event for a news organization — to lose one of its most prominent stars, especially under these circumstances,” said former CBS News President Andrew Heyward.

Now, viewers are more sophisticated and have many more viewing choices in the morning, diminishing the power of a prominent anchor like Lauer. “Times have changed to make the role of any one star less obvious than it was in prior decades,” Heyward said.

Other TV networks have proven to be resilient after their biggest names have been felled by scandals. Fox News remains the most-watched cable news channel in Bill O’Reilly’s old time slot, despite his firing over sexual harassment allegations. Lester Holt has fared well as Brian Williams’ replacement anchoring NBC’s “Nightly News” — two years after Williams was suspended for embellishing his experiences in Iraq.

Since Charlie Rose was fired Nov. 21 from CBS’s “This Morning” for alleged sexual harassment, the show’s ratings have dipped, though it’s still early. The decline may reflect people tuning out during the Thanksgiving holiday. Bloomberg TV, which like Bloomberg News is owned by Bloomberg LP, also stopped carrying reruns of Rose’s show.

Lauer may not be the main draw of “Today” anyway. Morning shows are typically driven by their female co-hosts, like Katie Couric, Diane Sawyer and Meredith Vieira, Klein said. If NBC can find a replacement for Lauer to pair with his co-host, Savannah Guthrie, and restore on-air chemistry, “Today” can continue to thrive, he said.

The Winter Olympics in February will be an opportunity for NBC to showcase the new Today team, Klein said. It would also be “a missed opportunity” if the network has not found a replacement for Lauer by then, he said.

It might even win over more viewers by replacing Lauer, who rates poorly among the public according to one industry measure of likability. Lauer has a Q Score of 11, meaning 11 percent of people who are familiar him say he’s one of their favorite TV personalities. That’s down from 23 percent at Lauer’s peak in 2010, said Henry Schafer of Marketing Evaluations, a market research firm that surveys thousands of viewers to devise the scores.

“He’s always been somewhat polarizing,” Schafer said. “Especially with the Ann Curry situation a few years ago. That didn’t go over well with consumers.”

To replace Lauer, NBC may look to its bench of other stars who fill in for him when he’s on vacation, such as Carson Daly, Willie Geist, Craig Melvin and Hoda Kotb. But in addition to likability, the network will have to consider whether the replacement has enough name recognition. For example, Geist has a Q score of 20, but only 16 percent of people are familiar with him, Schafer said. Half the population knows Lauer. Kotb and Guthrie have scores of 16, but are also less recognizable than Lauer.

In some cases, firing a big name host can lead to better things. When MSNBC dropped Don Imus in 2007 for making racial slurs, the cable news channel rushed to come up with a new idea. The result: “Morning Joe,” which has become one of its most popular shows.

“Sometimes these things can present an opportunity,” Klein said.