NEW YORK — Fox’s decision to plant “Temptation Island” on Thursdays is bad news for NBC’s already battered comedy lineup.

As if facing the CBS hit “CSI: Crime Scene Investigation” weren’t bad enough, Fox’s skedding of its mega-successful surf-and-sex reality skein at 9 p.m. means the combo of NBC’s “Will & Grace” and “Just Shoot Me” will face another serious threat in a time period the two shows once dominated in adults 18-49.

For Fox, which has played dead on Thursday for the past few years, the move means the net finally has a real shot at fixing one of its major ratings trouble spots.

“It’s a show that was enormously successful for us this past season, and it’s going to make a lot of noise for us on Thursday night,” Fox TV topper Sandy Grushow said.

Whether the second “Temptation” will prove as alluring to viewers as the original is uncertain. Some prognosticators wonder if viewers will return, since none of the original four couples split at the end of the first series.

“I think some of the luster will wear off,” Horizon Media senior VP of research Brad Adgate said. “I would be surprised if the ratings increased from its first season, especially since it’s in a tougher time period.”

Fox, however, can’t do much worse than the low-single-digit shares it’s been averaging on Thursdays.

And this time around, the trip to “Temptation Island” will be extended. Last season, the reality skein aired seven episodes; Fox will air about 10 next season, extending the show’s run into the first quarter of 2002.

Pundits had wondered whether “Temptation Island” would be announced as part of Fox’s fall lineup. Grushow, though, said, “There was never any question that ‘Temptation’ was going to wind up on the fall schedule.”

The racy reality show had difficulty selling ads in the past because of content issues, but Grushow said he’s not expecting that to be a problem this time.

Pix popular

Thursday, in particular, is a big night for movie advertisers who generally target young viewers — and Fox, along with CBS, will now be taking slices from a pie that once belonged almost entirely to NBC.

The Peacock’s one trump card remains “ER,” which has allowed the net to hold onto its Thursday crown this season in the face of the Eye’s “Survivor”-“CSI” challenge, although the medical drama fell to some record low ratings this season.

“Temptation” isn’t the only reality dish on the Fox menu. Net may bring back “Boot Camp,” and while “Police Videos” isn’t on the fall sked, it could return in the future.

Alternative topper Mike Darnell has several other projects in the works for next season, insiders said; if any one of them pops like “Temptation” did, Fox could meet its goal of winning a season among adults 18-49.

Official lineup

Meanwhile, at their upfront presentation on Thursday in Gotham, Fox execs officially unveiled their fall primetime sked, which includes two new dramas and three new comedies (Daily Variety, March 16).

While Fox sealed a deal for “The X-Files” to return for a ninth season, Grushow said negotiations with the show’s exec producer, Chris Carter, are still under way.

“At this moment, our expectation is that he’ll come back and run the show,” Grushow said. If he is not the showrunner, Carter would serve as a consultant, in which case Frank Spotnitz and Vince Gilligan would serve as showrunners, and John Shiban would be elevated to exec producer (Daily Variety, May 17).

David Duchovny will not return next season (Robert Patrick remains), but Gillian Anderson will appear in every episode, and newcomer Annabeth Gish will become a regular.

Grushow emphasized that while “Greg the Bunny” and “Andy Richter Controls the Universe” won’t be launched until midseason, that doesn’t indicate a lack of belief in the shows.

“We had more solid shows than periods to fill,” Grushow said.

(Josef Adalian contributed to this report.)