The expected dropoff in Jay Leno's ratings has begun.

 

Tuesday's edition of NBC's new 10 p.m. Leno strip notched a 3.3 rating/9 share among adults 18-49 and roughly 10.7 million viewers, according to preliminary fast national data. That's down sharply from Monday's debut in demos, and roughly 40 percent in viewers from Monday (5.1, 17.7 million prelim nationals).

 

Leno dropped from his "Biggest Loser" premiere lead-in (the reality show started off strongly; more later) and tied the final half-hour of CBS's "Big Brother" at 10:30 p.m.

 

There will be lots of media reaction to this big drop, but it's doubtful anyone at NBC (or rival networks) will be surprised. Monday's premiere was clearly about sampling, and nobody expected it to last, even for another day.

 

It'll be at least two weeks before Leno's true strength in the primetime marketplace can be tested.

 

In other ratings news, the CW's "Melrose Place" notched a 1.2/4 among adults 18-34, down from last week's 1.5. Not great, but not a disaster.

 

And "Biggest Loser" continues its ratings renaissance. It averaged a 3.8/11 and 9.9 million viewers, up 19 percent in the demo and its best fall premiere since 2004's series bow. Supersizing this franchise to two hours has proven to be a smart move for NBC, at least in the short term.

 

CBS's "Big Brother" (2.8/8) also ended with a bang, up four percent over last year's one-hour finale. Plus -- SPOILER ALERT!-- the awesome Jordan beat the awful Nat-a-lie, so really, all is well with the world today.