With just one week to go before the Fox News debate in South Carolina, the biggest star—and until recently a Fox News contributor—seems to be bowing out.Fox News executives had quietly extended the deadline for participation until May 3 to accommodate Newt Gingrich, seeing him as the event’s biggest draw. But that gambit has failed.“It's becoming increasingly clear that we're not going to make the deadline," Gingrich spokesman Rick Tyler told Hotline On Call. “We had always planned to be in the debate and want to be in the debate, but I don't think we will.”Fox News isn’t giving up or delaying the event, at least not yet. “We’re confident that we’ll have enough candidates to have a vigorous and worthwhile debate,” Fox Vice President Michael Clemente said in a statement.Pushing back the deadline may have given the impression that the network was doing its former commentator a favor and conveyed a frantic effort to salvage the debate, which is being spearheaded by Washington Managing Editor Bill Sammon. “Sammon was counting on Newt to participate,” says one person with knowledge of the situation. “This is a real blow to the debate.”So who’s in? Fox News expects to go with a lineup of Tim Pawlenty, Rick Santorum, Ron Paul, Gary Johnson and Herman Cain—although not all meet the established criteria, which includes forming a presidential exploratory committee and averaging at least 1 percent in recent national polls. Michele Bachmann could join if she forms a committee in the coming days, while Mitt Romney has not committed to the debate.Given the late-starting race, says Clemente, “in order to be as inclusive as possible, Fox News wants to make the deadline as close to the debate as possible in case there are late polls that may help candidates qualify. Any presidential debate is a reflection of the field at a given moment. As journalists, our job is not to marshal the field, but to take stock of the field by asking questions of those who toss their hats into the ring.”Since Gingrich has been weighing a White House run for a decade, does his all-but-certain withdrawal mean he’s leaning against running? Tyler sounded a note of caution, saying that “business entanglements” and “contractual obligations” are preventing his boss from legally forming a committee for now.