'American Idol's' Steven Tyler calls it quits Fox is poised to overhaul its most lucrative franchise after Thursday's announcement that Aerosmith frontman Steven Tyler won't be returning to"American Idol" as a judge. The 64-year-old rock singer's departure may be the first of a host of sweeping changes ahead for what was until last season, America's most dominant television series. "American Idol" co-judges Randy Jackson, who has been with the hit show since it began airing in 2002, and Jennifer Lopez, who is negotiating a new contract, could be the next to step away from the judges' table, according to sources. This week Lopez told the "Today" show that perhaps it was time for her to leave. Fox would not comment on any further changes. Tyler's decision comes after the singing reality series posted its steepest ratings decline ever - nearly 30% - last season. At the show's peak, its finale boasted more than 38 million viewers in 2003, but the May finale drew just under 21 million viewers this year. "I've decided it's time for me to let go of my mistress 'American Idol' before she boils my rabbit," Tyler said in a statement Thursday. I strayed from my first love, Aerosmith. For Fox, fixing "American Idol" is a priority. Until recently, its ratings were so strong that rival networks were afraid to compete with the show. It was nicknamed the "death star" for the way it destroyed competitors. But last season, "Idol" slipped and was beaten on occasion in head-to-head competition byCBS'sgeek sitcom"The Big Bang Theory." Advertisers paid a premium to be on "American Idol," which has been a cash cow for Fox. In 2011, it generated almost $700 million in advertising revenue, according to consulting firm Kantar Media, and has made billions for Fox's parent company,News Corp., since the show premiered a decade ago. Despite its sharp decline, the show's ratings, especially in a time of audience fragmentation, are widely envied by other networks. The show's appeal makes "American Idol" a vital promotional platform for Fox to market its other shows. This isn't the first time the show has staged its own version of musical chairs at the judges table. Lopez and Tyler joined "Idol" in 2010 after the departure of the show's governor, Simon Cowell, now of the Fox reality singing competition "The X Factor," and Ellen DeGeneres and Kara DioGuardi, both now gone, joined after Paula Abdul left the show in 2009 after eight seasons. For now, it appears the most stable public part of "Idol" is host Ryan Seacrest, who has been with the show since the start. This year, Seacrest renewed his contract with Fox for two years at the same $15 million he had been making when his contract expired at the end of last season. Tyler said his exit would enable him to focus on Aerosmith, which he's spent nearly 40 years fronting. It seems logical considering the band has a new record coming out and they are on tour - although Tyler had scheduled the tour to have breaks to accommodate his "Idol" duties. But a source close to the show told The Times that the rocker, who made $8 million to $10 million to judge, might have had his option for another year on the show dropped by the network - his contract was up Friday. "We are very sad that Steven has chosen to focus more on his music, but we always knew when we hired arock 'n' rolllegend, he would go back to the music," Mike Darnell, president of alternative entertainment for Fox, said in a statement. With the first round of next season's auditions, which does not yet require judges, in full swing, the clock is ticking to find a replacement. "Idol" alumnus Adam Lambert is a name that's been circulating as a possible new judge, although he has said there have been no talks. A Fox spokesperson would not say when the judges panel needs to be completed, but it's expected that a decision needs to be made by late September if the upcoming season is to stay on schedule. Times staff writer Gerrick Kennedy contributed to this report.