The waiting is sure to be the hardest part for NBC U staffers.

With the CEO shuffle at NBC Universal now set, following Sunday’s announcement that Comcast’s Steve Burke will succeed Jeff Zucker once the merger of Comcast and GE is complete, staffers at the Peacock are nervously awaiting word of their fate. It’s expected Burke will overhaul NBC’s management ranks once he takes the reins.

With so much uncertainty brewing inside NBC U’s broadcast and cable units, work is starting to slow down there — and that won’t change until there’s clarity in the exec suites at 30 Rock and Burbank.

“Now everyone there feels like there’s someone looking over their shoulder,” said one industry player with regular dealings at the Peacock. “It’s impacting the deals they’re making. Everyone’s beyond cautious. They don’t have much luxury to take risks at the moment.”

Outside NBC U, dealmakers are finding it more difficult to get things done with the company right now. And even if they sell a project or seal a pact, it may be with someone who will no longer be employed there in a few months — potentially leaving the deal to wilt.

NBC, of course, is still open for business, having recently given a put pilot to J.J. Abrams’ Bad Robot shingle for a drama starring “Lost’s” Michael Emerson and Terry O’Quinn. But the Peacock’s development had so far taken place prior to Zucker’s announcement on Friday, under the guise of “business as usual.”

Now that the facade of normalcy has finally been ripped clean and the buzz surrounding the future of NBC U’s management structure has intensified, it certainly won’t be “business as usual” until the merger is completed. Comcast and GE brass remain optimistic that the $30 billion deal for Comcast to acquire 51% of the Peacock will be completed by year’s end.

“This is an unstable situation that won’t hold,” one insider said. “We’re going to know sooner rather than later (what the new NBC U management structure will look like).”

The Hollywood parlor game of the moment, of course, centers on who’s coming and who’s going, as well as who will report to whom. Former Showtime entertainment prexy Bob Greenblatt’s name is on everyone’s lips, perhaps in a mega-entertainment job covering network and studio.

And on the cable side, Bonnie Hammer appears to be in the pole position for an expansion of her cable entertainment turf.

That still leaves question marks for NBC U TV Group topper Jeff Gaspin, Comcast’s Jeff Shell and Ted Harbert, and NBC U’s Lauren Zalaznick. There’s room for some, but no one expects everyone to make the transition.

“In some ways they have an embarrassment of riches, a lot of good executives,” one observer said. “But everyone wants more. And there’s not that much more to give.”

In announcing Burke’s appointment Sunday, Comcast and GE said in a press release that “there will be no additional structural or personnel announcements until the deal-closing process and timing is certain.”

A tenpercenter keeping an eye on the situation called that notion “a little naive.” “There are outside events that may trigger a change,” the agent said, suggesting that NBC U execs who aren’t thrilled with the new structure may be courted by rival media congloms.