'American Idol' sinks to record low in-season ratings Steven Tyler, please put your clothes back on. Thursday's "American Idol" delivered some of the show's lowest-ever numbers, although Fox blamed basketball more than the daffy judge's naked dive into a Las Vegas moat. "The Big Bang Theory" might have had something to do with it too. An average of 15.4 million total viewers tuned in to the one-hour "Idol," the show's lowest in-season numbers ever, according to early data from Nielsen (final data will be available later Friday). "Idol" hasn't seen numbers this low since it premiered back in the summer of 2002. Moreover, "Idol" was beaten in head-to-head competition during the 8 p.m. to 8:30 p.m. period by CBS' sitcom "Big Bang Theory" (16.1 million versus 14 million). "Big Bang" -- which has been putting the heat on "Idol" this winter -- was also the night's top show in viewers ages 18 to 49 (5.2 rating versus "Idol's" 4.4). Fox, which for a decade grew accustomed to piling up huge leads over rivals any night "Idol" was on, only managed to tie CBS in 18-to-49 on Thursday and lost in the total-viewer contest. For the record, Fox blamed the slide on the defection of male viewers to NBA basketball on cable (TNT featured a doubleheader including a Knicks-Heat matchup that delivered big ratings). But the fact that "Idol" got a sizeable bounce at 8:30 seems to suggest that the men are watching "Big Bang" then turning to "Idol." Or maybe people were just dreading seeing Tyler's backside? The judge decided to strip off his clothes and dive into the water at the Wynn hotel in Vegas. What do you think is behind -- so to speak -- "Idol's" decline? Steven Tyler strips as judges decide on "Idol" What's behind "Idol's" ratings erosion? "Idol" producer dismisses idea of "super-final" with "The Voice," "X Factor" Photo: "American Idol" has seen ratings declines this season.