It’s not a good year to be a show on the bubble at Fox.

With the network already looking ahead to a fall boasting such newcomers as “The X Factor” and “Terra Nova,” it isn’t going to have a lot of room for its crop of so-so players.

That means shows like “Lie to Me,” “Human Target” and even “Fringe” have reason to be concerned. Speaking to reporters Tuesday at Fox’s portion of the TV Critics Assn. press tour in Pasadena, Fox entertainment prexy Kevin Reilly admitted he faces several tough calls come May.

“Sometimes things have creatively drifted,” and it’s easy to cancel a show, he said. “But in all instances here, these are good teams, good stars, and I like the shows. It’s a shelf space issue. Not all shows are going to make it.”

Many of those bubble shows have hit a ratings wall, Reilly noted, pointing out that Fox does need room to cultivate new fare. “We need a next generation of hits,” he said.

Reilly cautioned not to write off “Fringe” just yet, however. The exec said he’d be happy if at least 80% of the show’s Thursday night viewers made the move to its Friday home.

“I’d be discouraged if the audience that has stuck with it already all of a sudden says, ‘I’m out of here’ because it’s on a new night,” he said.

One other show that still awaits its fate on Fox, but for an entirely different reason, is the long-running hit “House.” Reilly confirmed that the network and Universal Media Studios (the studio behind the show) have not yet begun negotiations on a renewal. Fox’s deal for “House” expires at the end of this season.

“It will be one of Mr. Green-blatt’s first jobs,” said Reilly, referring to incoming NBC Entertainment chairman Bob Greenblatt.

Among the other shows set for next fall: frosh sitcom “Raising Hope,” which scored an early second-season pickup from the net.

Fox opened its TCA sesh by announcing a firm “preview” date for the ambitious prehistoric drama “Terra Nova.” Show will get a two-night launch at 9 p.m. May 23 and 24 (behind the penultimate episode of “American Idol”).

The drama then returns officially in the fall (following an air pattern similar to the launch of “Glee” in 2009).

Fox Entertainment Group chairman Peter Rice dismissed reports that “Terra Nova” had cost overruns, noting the show’s pricey sets and special effects have been amortized over 13 episodes, not just the pilot. “That’s why we ordered directly to series,” he said. “It would be the most expensive first-year show we’ve had, but not the most expensive show on our air.”

Reilly said exec producer Steven Spielberg has been heavily involved in the creation of “Nova.”

“Steven’s had an unbelievable level of engagement,” he said. “He watches way more TV than I do, and he’s really up on it.”

Meanwhile, the question of Fox’s major fall disappointment, “Lone Star,” crept up again as the execs were asked whether the show could have been saved.

“The truth is it failed,” Rice said. “It doesn’t mean we don’t like the show.”

Reilly took issue with critics who turned “Lone Star’s” failure into an indictment of broadcast TV.

“I don’t believe for a second that all the great shows are just on cable,” he said. “Some commentary after the fact was not completely fair.”

As for the coming “American Idol” and “X Factor” one-two punch, the execs dismissed concerns that the broadcasters would be overly saturated with performance competition series — at least on their air. “We have the biggest and largest in ‘Idol,’ ” Rice said. “And ‘X Factor’ has Simon Cowell. They’ll run at different times of the year. And ‘X Factor’ is very different from ‘Idol.’ ”

That said, Reilly admitted there probably wasn’t room for the crush of dance and singing competitions coming to TV in the coming year. “We’ve got the gold standard,” Reilly said. “Everyone else is trying to chase it.”

In other announcements, Fox said that its sketch comedy series from Jamie Foxx, along with comedian Affion Crockett, will get a sneak preview at 9 p.m. March 31 behind “Idol.” Show will regularly air this summer on Thursdays at 9 starting June 9. The as-yet untitled show comes from Fox TV Studios, Foxx/King Entertainment and Tantamount. Foxx, Todd Yasui, Marcus King, Jaime Rucker King, Eric Tannenbaum, Kim Tannenbaum and Mitch Hurwitz are exec producers.

Also, Fox announced that former “So You Think You Can Dance” judge Mary Murphy will return to the show, alongside Nigel Lythgoe, this summer.