Discovery CEO David Zaslav just added another big item to his long to-do list in preparation for the WarnerMedia-Discovery merger: Find a strong replacement for CNN chief Jeff Zucker.

Zucker shocked the industry by stepping down from WarnerMedia, where he was CNN president and chairman of news and sports for WarnerMedia, after an investigation into the conduct of now-fired CNN anchor Chris Cuomo revealed that Zucker had not disclosed that he had a consensual romantic relationship with a colleague. The colleague who went unnamed in Zucker’s resignation memo to staff is Allison Gollust, CNN’s chief marketing officer and a longtime Zucker lieutenant going back to their respective tenures at NBC.

Sorting through plans for leadership ahead of AT&T’s $43 billion spinoff of WarnerMedia to Discovery, which is expected to close in the second quarter, is already a huge challenge for a deal of this size. But Zucker’s abrupt resignation leaves Zaslav, who will be CEO of the newly minted Warner Bros. Discovery, with an immediate problem at a time when the deal is in regulatory review limbo. Moreover, CNN is one of WarnerMedia’s most important assets and a huge driver of bottom-line earnings for its parent company. CNN is also in the midst of preparing for the launch this quarter of its CNN Plus streaming platform. Zucker has been busy in recent months recruiting talent and shaping programming plans for the streamer.

“I think the expectation from everybody, inside both Warner and Discovery, was that Jeff would stick around, at least for the first portion post-merger,” a source close to the situation told Variety. “The merger still has to be approved, obviously. But in the event that it does — and as of right now, all signs seem to point in that direction — there was the idea that he would probably be sticking around to be a part of CNN.”

The source noted that Zucker and Zaslav have a long relationship that dates back to the late 1980s when both were up-and-coming executives at NBC. But the situation was clearly untenable for WarnerMedia. Zucker acknowledged in his memo to CNN staffers that he should have disclosed the relationship. Moreover, given the larger cultural changes spurred by the #MeToo movement, scrutiny of senior managers has become heightened, which means the Zucker-Gollust relationship would have been a major headache for the incoming regime.

“The sole focus, at Discovery is to go through the steps appropriate to get closer to closing the merger,” the source said. “It does certainly leave a giant question mark in terms of who will be leading CNN on Day 1 because I think everybody would have said that it was going to be Jeff.”

Along with leading CNN, Zucker also oversaw Turner Sports, another critical asset, and supervised the majority of WarnerMedia’s live programming.

WarnerMedia on Wednesday named Michael Bass, Amy Entelis and Ken Jautz to run CNN on an interim basis until the merger with Discovery is completed. “I have accepted Jeff Zucker’s resignation as Chairman of WarnerMedia News and Sports, and President of CNN Worldwide. We thank Jeff for his contributions over the past 9 years,” said Jason Kilar, WarnerMedia CEO. “Both of these organizations are at the top of their respective games and are well prepared for their next chapters.”

Several observers believe Entelis would be a prime candidate to run the news operation, in large part due to her close ties with many of the anchors and personnel, and because of her oversight of CNN’s push into documentaries, original series and films. But there is also some speculation that she may not want the top role on a long-term basis. Bass is a longtime Zucker lieutenant who runs most of the network’s programming, while Jautz is viewed as essential to CNN’s logistics and operations.

However, a second source pointed out that though there was a lot of speculation that Zucker was a shoo-in to stay with the Warner Bros. Discovery-owned CNN, Discovery has not guided or fed that perception.

Per industry insiders, AT&T and Discovery think the transaction could close as soon as early April, though that is subject to an OK from the Justice Department. When formed, the new company’s board will comprise 13 members, seven initially appointed by AT&T, including the chairperson of the board. Discovery has six seats, including Zaslav.

A source close to the situation said it was doubtful that the interim CNN leadership team would stay in place long term. Zaslav is expected to recruit a heavy hitter with significant news experience. Discovery has a strong bench of executives who have worked with Zaslav for some time, including those with sports experience through Discovery’s Euro Sport unit. Zucker’s hasty exit could open opportunities for reconfiguring news and sports operations for some of those lieutenants that otherwise would have been blocked by Zucker’s prominence. Discovery business development chief Bruce Campbell and Discovery International chief JB Perrette have been mentioned as executives that could gain turf as top management roles are sorted out for the enlarged company.

“It’s a totally new conversation. I don’t think there’s any intention to just continue with the existing interim (CNN) leadership,” the source told Variety.

On Wednesday, Discovery stock closed at $27.69 per share, up 1.9% from where it opened. AT&T stock closed at $24.54, up less than 1%.

(Pictured: Jeff Zucker, David Zaslav)