A low note on ratings for ‘Idol’

Have “American Idol’s” ratings entered their over-the-hill, Elvis-in-Vegas phase?

Fox’s hit singing competition returned for its seventh season with a two-hour Tuesday premiere that averaged 33.2 million total viewers, according to preliminary results from Nielsen Media Research. That’s a huge number, by a large margin the most-watched entertainment telecast so far this season.

And needless to say, it blew away the competition: The night’s next most-watched show was CBS’ “NCIS,” which logged 15.9 million viewers. It also stomped NBC’s “The Biggest Loser” (7.2 million), which had been benefiting from a lack of competition due to the ongoing Writers Guild of America strike.

Even so, a sense of diminishment hung in the air. For the first time since it became a winter TV staple back in 2003, “Idol’s” season premiere did not improve on the previous year’s debut. Not only was “Idol” down 11% compared with last season’s all-time high for a season opener (37.4 million), it actually delivered the lowest premiere figures, among both total viewers and the crucial demographic of adults ages 18 to 49, since 2004.

The slippage comes as “Idol” has faced criticism over its content, sometimes from people close to the show. The producers have said the sixth season spent too much time with celebrity mentors at the expense of the contestants. Critics felt last year’s competition was hijacked by a distracting controversy over Sanjaya Malakar, a teenage crooner with ever-evolving hairstyles. In a Rolling Stone interview, Chris Daughtry, the fourth-place finisher in 2006 and now a popular rock musician, said “Idol” is “lacking some credibility at this point.”

Even so, Tuesday’s numbers are not necessarily a reliable indicator of overall waning interest in “Idol.” The ratings can build as the field winnows down and viewers get engrossed in the rivalries among the contestants. And as the writers strike wears on, “Idol” may benefit from rival networks forced to rely on repeats and lesser-known unscripted shows.

The Channel Island column runs every Monday in Calendar. Contact Scott Collins at scott.collins @latimes.com