CBS, which pulled off an unprecedented third-to-first place primetime turnaround during the 1991-92 season, is in danger of concluding the 1994-95 campaign back in the ratings cellar.

The Eye network, after three years as the top-rated network, is also on the verge of another dubious achievement – currently trailing Fox Broadcasting Co. for the season among adults age 18-49, one of the major demographics (the other being age 25-54) sought by advertisers.

With CBS Entertainment prez Peter Tortorici publicly vowing not to let the network sink into the sunset on his watch, and other distractions – not the least of them being persistent speculation that chairman/CEO Laurence Tisch will sell the network – to fret about, Eye web officials are starting the arduous task of rebuilding their primetime schedule.

The catch, of course, is that the audience CBS currently attracts doesn’t provide much of a launchpad for creating new franchise shows, whereas ABC, NBC and even Fox have the advantage of introducing programs behind youth-oriented hits like “Home Improvement,” “Seinfeld” and “The Simpsons,” respectively.

Tortorici points out that CBS is managing to keep overall circulation relatively high in terms of viewers as it seeks to reconfigure its lineup, though the web’s double-digit declines in key demos are of particular concern. Looking to the coming season, the exec notes that conventional wisdom says not to introduce more than seven hours of new programming at a time, but he also acknowledges that the web has “a lot of problem areas” to address.

CBS can attribute part of its decline to natural attrition, as well as a failure to generate new hits as established franchises – like “Murphy Brown,” “Rescue 911” and “Dr. Quinn, Medicine Woman” – started to fade.

The network also faced a standard problem that follows success, being fettered by commitments to big-name suppliers. As a result, a border-line series like Diane English’s “Love & War” stayed behind “Murphy Brown” for three seasons, only to watch “Murphy” gradually lose viewers without providing a springboard for launching new hits. Asked to go stand on its own behind a new Shukovsky English Entertainment series, “Double Rush,” “War” has been barely able to muster double-digit shares.

Like Brandon Tartikoff s fortuitous timing at NBC, former CBS Entertainment prexy Jeff Sagansky left last spring, leaving Tortorici to grapple with that network’s programming puzzle. “He inherited a heap of trouble,” as one programming exec put it.

While more scheduling changes are planned this spring (the network will introduce new sitcoms starring George Wendt and Valerie Harper in March), CBS is focusing its attention on development for the coming season – particularly on high-profile producer and star deals.

Reliance on such star power has produced dubious benefits in the past (witness shows with the likes of Faye Dunaway, Dudley Moore and Shelley Long), but programmers still see advantages in having a familiar, pre-sold personality in introducing a new series.

CBS has thus made a 22-episode commitment to Don Johnson and is also developing projects around Scott Bakula, Cathy Moriarty and Andrew “Dice” Clay, Joan Cusack and Joan Rivers. Filmmakers Gary David Goldberg, Sam Raimi and Nora Ephron (with producer Janis Hirsch) are also working on shows, as is “Forrest Gump” writer Eric Roth.

The real emphasis, however, is on attracting younger viewers. CBS recently snapped up a script for a sci-fi project, “The Tomorrow Man,” from producer Alan Spencer and is determined to create some 8 o’clock shows with more youth-appeal. Earlier, CBS extended series commitments to Darren Star, the creator of “Melrose Place” – a show that hardly attracts the same audience as “60 Minutes” and “Murder, She Wrote” – and to a romantic sitcom from Larry Levin, who created Fox’s hip if short-lived comedy “Bakersfield, P.D.”

CBS also hopes big-event programming can help mask some deficiencies, with all-star miniseries like “Buffalo Girls” and “Streets of Laredo” (both Larry McMurtry adaptations) planned for May and November, respectively. The web won the November sweeps behind the eight-hour “Scarlett” but is trailing at the start of the February survey.

The best news for CBS, perhaps, may be that it’s not the only net with headaches as it approaches ’95-96.

ABC has watched “Roseanne” show distinct signs of aging this season and has been unable to create new comedy hits from 8-9 p.m. Tuesday and Wednesday – with the distinct threat that “Full House,” one of its anchor shows, may not return next season.

NBC has built its resurgence largely on the strength of its Thursday-night heavyweights “Seinfeld,” “ER,” “Mad About You” and “Friends,” and gains achieved by moving “Wings” and “Frasier” to Tuesday. On the down side, the web has several timeslots that still need shoring up, and Jerry Seinfeld has yet to sign for another season of his show, indicating that even if he does, the 1995-96 term could be its last.

J. Max Robins contributed to this report.