Who will replace Simon Cowell on ‘American Idol’?

The future of “American Idol,” once the most watched program in America, hangs in the balance with the departure of Simon Cowell.

The sharp-tongued British judge who helped bring the ‘Idol’ franchise to the U.S. was—along with the wannabe pop stars—the show’s main draw. His sardonic on-air persona coupled with his musical authority made him an integral part of the ‘Idol’ brand, which depended as much on his acerbic commentary as it did on unearthing the next big pop star.

His notoriously harsh criticisms were both beloved and reviled by audiences, who sometimes took to judging the judge with verbal expressions of praise or disappointment. It was Cowell’s opinion that became the primary predictor influencing the larger culture, and his tendency to spot big talent early on often made his fellow judges look like amateurs.

Cowell was also good for ratings. Along with his witty one-liners and brutally honest critique, Cowell’s explosive—and sometimes sexual—chemistry with co-stars provided the show with some much needed drama. There’s no doubt audiences missed his playful sparring with Paula Abdul this season, even though he and Ellen DeGeneres tried to forge a comparable rapport (in a sad twist of irony, DeGeneres, who was likely chosen for her comedic gifts brought little comedy to the table). Simply put, Cowell was one of the show’s most entertaining elements.

Now at the end of their ninth season, “Idol” is facing the loss of its star player and, for the first time, a ratings decline. So execs at Fox are scrambling to find a worthy replacement who might draw ambivalent viewers back into the fold.

About a month ago, rumors swirled that Season 8 runner-up Adam Lambert might take Cowell’s spot on the judges’ panel, but Lambert has since said he plans to focus on his music career (a wise choice). Then came another rumor that radio host Howard Stern might get an offer—but his declaration that it would take $100 million likely stunted any potential. Not to mention, Stern’s racy humor is hardly a match for “Idol’s” family-friendly demographic. Then again, a healthy dose of Jewish humor might go a long way.

Other names that have been tossed around include Elton John, Jamie Foxx, blogger Perez Hilton and former Sony music exec Tommy Motola. So far, Fox has been mum about Cowell’s replacement, though an announcement is expected any day.

But frankly put, Cowell is irreplaceable. His greatest gift throughout nine seasons on “Idol” was his unrelenting, unmerciful criticism. Time and again, Cowell’s voice gave the unreality of “Idol’s” instant-fame-and-fortune formula a real-world reality-check.