The Plot thickens at "Good Morning America."

Buzz at ABC is that co-anchor Diane Sawyer is lobbying management to hold off announcing her "GMA" replacement until after she leaves for "World News."

News division chief David Westin wants to release the name in early December, according to ABC insiders -- approximately a month before Sawyer replaces retiring anchor Charlie Gibson on "World News." No date yet for her "GMA" swansong.

If ABC agrees to sit on the announcement, it would keep all the attention on Lady Di and leave the No. 2 morning show with precious little time to promote her successor. "GMA" staffers are miffed at both prospects, the sources say.

ABC spokesman Jeffrey Schneider says "there is no truth whatsoever" to the Sawyer buzz.

Then there's Robin Roberts, "GMA" co-anchor since 2005 and a regular contributor for 14 years while at ESPN.

Her contract is up in April. If she's not guaranteed equal footing with the new co-anchor - no matter who it is - don't look for her to re-sign, sources say.

If it's candidate George Stephanopoulos of "This Week," who anchored "GMA" Wednesday through today, it could set up a real Catch-22.

Here's why:

The only way Stephanopoulos would take the job is if ABC were to re-design the show around him, sources say. He'd get first crack at the heavy political interviews, leaving Roberts with the postmortem of "Dancing with the Stars."

Roberts, however, won't put up with being big-footed. After years as a loyal team player and No. 2 to Sawyer, she will not settle for anything less than full equality.

"We're not anywhere near making a decision," Schneider says. "To talk about who the show is shaped for is, literally, ridiculous speculation."

Let's not forget "GMA" news reader Chris Cuomo. Sawyer, his mentor, has been urging him to lobby for a spot at "World News," where his hard-news reporting skills would get more exposure, sources say.

Ridiculous, Schneider says. Again.

Will it happen? As anyone at ABC will tell you, when Sawyer goes after something, it would take an act of Congress to dissuade her. If it doesn't happen, Cuomo might not re-sign, either, sources say.

For her part, Sawyer has told "World News" staffers she won't make any changes for six months, sources say. At that point, who knows? Don't be surprised if she brings in Jim Murphy, her "GMA" boss and former executive producer of "CBS Evening News," as EP.

Says Schneider: "Jon Banner is executive producer of 'World News' and will continue to be... The idea of some timetable is absurd."