A Princess of Mars:According to Variety, Robert Rodriguez's resignation from the DGA has jeopardized Paramount's development of its tentpole pic A Princess of Mars.

The problem: As a DGA signatory, Paramount is required to employ only guild directors.

Rodriguez's recent move to leave the DGA was triggered by his desire to co-direct Sin City for Dimension Films with Frank Miller, who created, wrote and illustrated the three-book graphic novel series on which the Sin City pic is based.

"We are in discussions with Mr. Rodriguez and are trying to come up with a solution," said Rob Friedman, vice chair and chief operating officer of Paramount's motion picture group.

Insiders close to Rodriguez insist that -- at least for now -- he is unwilling to rejoin the Directors Guild just to direct Princess of Mars.

DGA rules dictate that there be only one director assigned to direct a motion picture at any given time, although the guild occasionally grants a waiver, such as with the Coen brothers.

The DGA issued the following statement: "When it comes to creative judgment, vision, leadership and decisionmaking ... co-directing generally does not work. Having said that, there are exceptional circumstances where two individuals have demonstrated an ability to reflect a singular vision through previous directing experience, which the DGA has always supported through the granting of waivers to bona fide co-directing teams."

Rodriguez, who is in production in Austin, Texas, on "Sin City," was not available for comment Thursday. When Rodriguez resigned last month, he portrayed his departure as reflecting his unorthodox plans for "Sin City" -- such as having Quentin Tarantino helm part of the film, possibly using a "special guest director" title that would not be available under DGA guidelines.

Rodriguez also quit the DGA a decade ago so he could take part in the Tarantino-orchestrated film "Four Rooms." He told Daily Variety last month that the co-directing credit for Miller would more accurately reflect how the film will be made.

"I didn't want Frank (Miller) to be treated as just a writer, because he is the only one who has actually been to 'Sin City,' " Rodriguez said. "I am making such a literal interpretation of his book that I'd have felt weird taking directing credit without him."

Mark Protosevich is scripting; cast has not yet been set. Budget is said to top $100 million due to extensive CGI. Goal is to match the scale and scope of the Lord of the Rings trilogy.