TV ratings juggernaut "American Idol" returns next week for a ninth season with comedian Ellen DeGeneres joining the judging panel but a big question mark hanging over the future of the show's biggest star -- Simon Cowell.

Despite slipping ratings for the past three years, the singing contest is expected to remain the jewel in the Fox network's crown as the most-watched show on U.S. television and the birthplace of the next potential moneymaker for the struggling record industry.

Rampant rumors, neither confirmed nor denied, that abrasive British judge Cowell will bow out when his contract ends in May, the replacement of Paula Abdul with DeGeneres, and a gaggle of star guest judges will likely boost interest for the two-hour premiere on Tuesday, Jan. 12, industry watchers say.

But after the initial shows -- and after seven years of earning top dollar from advertisers, a No. 1 ranking from audiences and the envy of rival networks -- "American Idol" faces a critical year.

Audiences slipped to an average 26.3 million viewers per each twice-weekly episode in 2009 from a 2006 high of about 30.8 million, and "Idol" advertising sales fell in 2009 to $858.6 million from $903.3 million in 2008, according to TNS Media Intelligence.

"It is rare to see any pop culture phenomenon sustain that kind of momentum and those kind of ratings year in and year out. So it is natural to ask when the bubble will burst," said Entertainment Weekly's Michael Slezak.

"I don't think we are quite there yet. The show could take a ratings hit and still be top of the heap. No matter where 'Idol' comes in, I'm sure the numbers will be the envy of all of Fox's competitors," Slezak said.

DeGeneres joins the show as a judge along with Cowell, Randy Jackson, and last year's newcomer Kara DioGuardi.

The popular TV talk show host was named last summer to replace Abdul, who quit when "Idol" producers would not meet her demands for a new contract.

DeGeneres told her TV audience last week that she planned on being kind, empathetic and truthful. "I will be an honest judge without being mean," she added.

But she will not be appearing on the show until February, when a few hundred out of tens of thousands of hopeful singers who auditioned across America are sent on to Hollywood.

Pop stars Victoria "Posh Spice" Beckham, Katy Perry, Mary J. Blige, Avril Lavigne, Joe Jonas and Shania Twain are among the judges taking Abdul's place in the early audition rounds.

"The show now has two very big stars in Ellen and Simon," said Todd Gold, managing editor of Fancast.com.

"The curiosity factor is really going to help the show. But is it definitely a transitional year. Simon is at the center of one of the biggest and potentially costliest dramas in TV," Gold said.

Speculation over Cowell, 50, flared anew in December when his brother said in a radio podcast that Simon would leave after the 2010 season to focus on bringing one of his British singing talent shows, "The X Factor", to U.S. TV in 2011.
Cowell's publicist, Fox, and "Idol" producers all declined to comment.

Online betting sites are already speculating on a possible replacement with "America's Got Talent" judge Piers Morgan and singer Sean "Diddy" Combs leading the pack.

Gold and Slezak said that "Idol", which has produced Grammy winning stars like Kelly Clarkson and Carrie Underwood and is broadcast live or tape-delayed in more than 100 countries, would take a ratings hit should Cowell leave, but would not go off the air.

Still, even before the show starts, talk has surfaced that it could take a major hit if he leaves. DeGeneres, who signed a five-year contract with "Idol," told Entertainment Weekly magazine in its new issue: "If Simon goes, I go!".

Cowell replied that put him in a "tricky situation."

"I think right now we have to concentrate on the next season and just get through that and worry about everything else afterwards," Cowell told Entertainment Weekly.