NEW YORK — In a dramatic changing of the guard at NBC, news prexy Andrew Lack has been upped to president and chief operating officer effective June 4, replacing Bob Wright, who was named Peacock chairman-CEO.

Move — a clear sign, insider say, that Lack’s now Wright’s heir apparent — is a nod to Lack’s resounding success at NBC News, which he’s run since 1993. He oversaw the launch of MSNBC, the expansion of “Dateline” and the rise of “NBC Nightly News With Tom Brokaw.” NBC’s morning show “Today” continues to be the ayem leader.

He’s the second NBC News exec to be named to a key Peacock post. Former “Today” exec producer Jeff Zucker became entertainment prexy in December.

“I can’t get away from him,” Zucker joked. He said Lack’s appointment makes perfect sense. “Andy has been as important to the success of NBC over the past 10 years as anyone. He’s now going to do for NBC what he’s done for NBC News.”

Lack will continue to report to Wright. He will oversee entertainment, NBC News and MSNBC, NBC Stations, CNBC, operations, sales and affiliate relations and NBC Cable. He will also become a member of the corporate executive council of NBC’s parent company General Electric.

While continuing to serve as vice chairman and executive officer of GE, Wright will continue to be responsible for sports and Olympics, CNBC Intl. and all of NBC’s staff operations.

Welch retirement looms

The shuffle comes as GE’s chairman Jack Welch is preparing to retire later this year. Wright said he plans to devote more time to helping Welch’s successor Jeff Immelt get up to speed.

“I want to make it clear that I will remain extremely involved with NBC. But as Jeff Immelt takes over the helm of GE, one of my key duties becomes providing Jeff and GE’s top leadership with advice on broadcast and media issues,” Wright wrote in an internal memo to NBC staffers.

NBC is expected to announce later this week that “Dateline” exec producer Neal Shapiro will succeed Lack as head of NBC News. Industry insiders said NBC News VP David Corvo is a front runner to replace Shapiro as exec producer of “Dateline.”

Wright, now in his 14th year at the helm of NBC, is the longest-serving network head in history. He wouldn’t speculate about whether Lack will eventually succeed him. “The announcement speaks for itself,” he said cryptically.

Some see Lack’s appointment as a snub to NBC’s West Coast prexy Scott Sassa, whose contract with NBC expires this year. He will report to Lack now, not directly to Wright. Wright did his best to dispel the notion of any tension in the ranks. “Scott is a very significant part of our West Coast operations. He’s done a very good job. I hope and expect that Scott will be with us for a long time,” said Wright.

Tougher competition

Both Lack and Sassa have their work cut out for them at NBC Entertainment as the net’s primetime sked faces tougher competition than it has in years.

Next week, the Peacock will unveil its primetime sked to advertisers in its upfront presentation in Gotham. While NBC continues to reign in primetime among the key ad-friendly demo of adults 18-49, CBS upset the net’s longtime Thursday night dominance with one-two punch of “Survivor” and “CSI.” Although the web has recently had success with the Brit import game show “The Weakest Link,” NBC has been criticized for being way behind the curve in jumping into reality TV.

“The fact is that in many of our dayparts, more people are watching us than ever before,” said Lack. “On a ratings basis, the company is in great shape.

Escalating programming costs are also a challenge for NBC and its competish. “We can afford to pay for the ‘ER’s and the ‘Frasier’s.’ Not every show is a winner for us. Not every show is as profitable as we like, but we’ve got enough of them to make a good business out of it,” Lack said Tuesday in a television interview.

‘Great broadcaster’

Lack has never overseen entertainment programming, but NBC insiders say he has been a regular presence at entertainment programming meetings. As he has in the past, last week, he attended pilot screenings in Los Angeles. “It’s not as if he’s never read a script,” said one source.

“The fact is that Andy is a great broadcaster with a great eye. Those are the skills that are transferable whether it’s news, sports or entertainment,” said Zucker, who faced similar skepticism when he jumped from news to entertainment.

Lack isn’t the first news producer to become a network prexy. Howard Stringer was president of CBS News before being named to head up the Eye net in 1988,

Lack’s ego has earned him his fair share of bad publicity. In 1997 when, after battling with his longtime rival Fox News topper Roger Ailes over Geraldo Rivera’s contract, Lack boasted to the New York Times: “I am America’s news leader.”

After that, Lack tended to keep a low profile with the press.

Still, Lack is largely credited with helping to bring some of the luster back to the Peacock’s news division. He filled the hole created by the forced departure of the previous news prexy Michael Gartner, who left the network under a cloud of controversy following a “Dateline NBC” report in which a General Motors truck was rigged to catch fire on impact.

Lack was named to lead NBC’s news division after a 17-year career at CBS News where he worked as an on-air correspondent before moving behind the camera to produce documentaries and newsmags. He created “West 57th,” the CBS newsmag that ran for four seasons, and exec produced “Face to Face with Connie Chung,” “CBS Reports” and “Street Stories.”