Here's what Bluth patriarch Jeffrey Tambor said about the matter, as related to the NYDN:

Michael Cera will do the highly debated “Arrested Development” movie, according to his on-screen granddad, Jeffrey Tambor.

“If I have to call him up and say, ‘Get on set right now, young man,’ he’ll be there,” the comic said at a recent Upright Citizens Brigade L.A. performance of “Word Girl.” “The movie is going to happen this year, and Michael Cera is on board. Trust me.”

We're not going to believe it until we hear it from Cera's mouth, but it's still encouraging that at least one cast member has vowed to grab him by the hoodie and drag him onto set if need be. They aren't just handing out big-budget superhero movies to skinny Apatow players anymore, Cera—take the four-week gig for peanuts, assuage your fanbase, and then move on to the next installment of your unofficial film series: Stammering Guitarist Finds Awkward Young Love.

• 'Arrested Development' movie is on! [NYDN]

We've got video above where Howard tells the hosts of Morning Joe that the film isn't quite greenlit yet and will need a completed script first— a comment which reminded us that creator Mitchell Hurwitz said he can't write the script until he knows which actors are on board. If only there were some sort of shared (three-season-long) history between Hurwitz and Cera to instill faith in the erstwhile George Michael.

In other news, it's been pointed out that we missed this little tidbit from TCA, which necessitates a Film Tracker update:

Count Portia de Rossi in for an Arrested Development movie: Despite calling her new character in ABC's Better Off Ted her all-time favorite, she'd be up for reprising Lindsay Bluth on the big screen. "I would love to do a movie for Arrested," she said — before adding to the confusion surrounding the project by saying "the cast are all on board." If that gets off the ground, she'd be a busy lady: She also wants to start a vegan shoe line.

And with that, the Film Tracker is complete: each and every actor, director, and trade paper has weighed in, and Cera is the lone holdout (lacking even a powerful excuse like the demands of a hemp-derived shoe company on his time). Come on!

• Ron Howard Defends "Punk" Michael Cera, Talks "Arrested Development" Movie [HuffPo]

MTV cornered the actor to ask just what exactly was the holdup, and Cera—while fully embracing his unlikely new role as a meddling antagonist—explained that he wouldn't sign on because there's no script yet. Of course, as creator Mitch Hurwitz has explained, there won't be a script until Hurwitz knows for sure which cast members are coming back. What a hilarious, Arrested-worthy Möbius strip of stalled misunderstandings. We are never getting this movie.

• Michael Cera On ‘Arrested Development’ Movie: ‘More Hypothetical Than People Think’ [MTV]

Despite the fact that nearly every cast member has signed on (though we're still waiting for Portia De Rossi to finish restocking Ellen's green room with votive candles so she can issue an official announcement) and creator Mitchell Hurwitz says he can't proceed in writing a script until he knows whether Cera will commit, the actor has remained indecisive, Bateman said at TCA.

"I think you really have to get him on the phone to get his answer about whether he's going to come back and do it or not. I know he's thinking about it, and we're all awaiting some finality to that."

"I do feel bad that people are a little misinformed about what's going on with him," Bateman said. "He's certainly not said that he won't do it. I think he's, you know, Michael is clearly the guy that has come out of 'Arrested Development' with a very, very big plate. And so I think he's trying to really give some responsible thought to what makes sense for him to do with his career.

"The guy's 20 years old and I'm sure he doesn't want to screw up this opportunity, and trying to figure out whether an 'Arrested Development' film would be right for him and his future, I think, again, he's just trying to give responsible time to that decision. And he may or may not have come to a decision. I really can't speak to that."

If Cera hasn't come to a decision, he might be forced to after a rabid Sundance press pack accosts him over the next week. There have been many times in history when a fine, upstanding Bluth was pressed into service because the members of his family demanded it; Michael, we ask you, what's one more?

• Bateman Defends Cera's 'Arrested' Decision [Fancast]

• Michael Cera Still Not Signed for Arrested Movie [E!]