James Spader addresses the troops on The Office. Photo: Ron Tom/NBC

Next month will mark one year since Steve Carell left The Office and took Michael Scott with him. There’s been plenty of tumult since for the Scranton clockpunchers, from a painful (and celebrity-filled) search for his replacement to the arrival of James Spader’s predictably creepy Robert California. Ratings for the show are down from last year, when Carell’s pending exit artificially boosted numbers, and there has been some fan grumbling that The Office isn’t the same without him. And yet, even in its eighth season, it remains far and away NBC’s top-rated Thursday show, and its biggest scripted series overall among viewers under 50. In recent weeks, the show has also made headlines for some behind-the-scenes activity: a report of a Rainn Wilson–led spinoff, confirmation that Spader’s gig will end after one season, and continued rumblings about various writers and actors possibly departing after May. Series showrunner Paul Lieberstein (who also plays Toby) hasn’t done any extended interviews since all of these stories started breaking, but yesterday, he broke his silence to Vulture. We quizzed him about the rumors, got his take on Spader’s impact on the show, pressed him for spoilers about what’s to come for the rest of the season and got him to address the ultimate question for any long-term fan of the show: How long does he think the show can go on? Below, we’ve culled 11 of the most interesting revelations from our nearly hour-long chat — including news of a guest turn by a veteran of The Wire and True Blood.

James Spader’s departure wasn’t entirely unforeseen.

“We always kind of thought of this as a transition year,” Lieberstein says, explaining that a one-year gig at Dunder-Mifflin “was what we had talked to [Spader] about when” negotiations for him to join the show began. “It was just kind of fun, living in the moment and just enjoying his presence, and not really planning what it was going to be like in seasons to come,” he adds. Some critics have suggested Spader’s character didn’t seem to fit well into the Office universe, but Lieberstein says he didn’t have any trouble working him into the show. “He was this kind of bizarre, fascinating character who could create his own reality,” he says. “When he was in the show, I never really questioned why he was in. I thought we found a lot of interesting things to play with him; as his life changed, opened up, we learned about his marriage, his divorce. And I loved his relationship with Andy, too.” California’s final appearance will be in the show’s season finale, and his exit will be a definitive departure, Lieberstein says.

Missed having one, Michael Scott-like character at the center of the office? The producers do, too.

Post-Steve Carell, The Office this season has boasted what Lieberstein calls a “rotating center. We always had a center, but it wasn’t a single one for the whole year.” So for some episodes, Andy was out front; in others, Robert California. Most recently, the show has been focused on the relationship between Jim and Dwight as they work together in Florida, as well as on new foil Nellie (Catherine Tate). Lieberstein says the shifting focus was intentional (“We knew we were going to do it,” he says), but hints that next season, there might be a switch back to how things were during the bulk of the show’s run. “I have a romantic feeling for the simplicity of the single-manager structure,” he says. “Next year might see a return to it.” Not surprisingly, Lieberstein wouldn’t elaborate further, except to say that there almost certainly won’t be multiple layers of management at the Scranton office.

The final stretch of episodes this season will pit Andy vs. Nellie (Catherine Tate).

When the Florida team returns to Dunder-Mifflin’s Scranton branch after the six-episode arc (tonight is number four), Nellie will come with them, and she will immediately make her desires clear. “They offer her a desk in the office, but she goes to [Andy’s] desk and says, ‘No, I prefer this one’,” Lieberstein explains. “She makes a play for Andy’s job. The rest of the season is this power struggle between them.” This will be good news for fans of Original Recipe Andy: “We’ll see his old anger management issues come out within this struggle,” the producer says.

The temp’s play for Jim is over.

Pam’s maternity leave replacement, Cathy (Lindsey Broad), didn’t have much to do during her stay at the office, but Lieberstein says her attempt to hook up with Jim was not a left-field plot twist. “We played it slow; that was our intent,” he says. “If you were bored and really watching, you’d see clues to it [throughout her arc]. She always had eyes for Jim.” But now that Jim rejected her advances? “That’s it,” Lieberstein says.”I think he put it to rest.”

But the Andy-Erin romance may be heating up again.

Andy will soon learn of Erin’s plans to relocate to Florida, and “it’s going to force him to act and to try to get her back,” Lieberstein says. Why was he so slow to respond to Erin’s obvious attempts at a reconciliation? “He was hurt [by her earlier rejection], and then he started to date someone else,” he says. “He had started to move on and wasn’t ready to look back.” Lieberstein promises we won’t have to wait long to find out: It will be “in a couple of episodes,” he says.

The Florida arc was all about turning the show’s focus to Dwight and Jim.

Lieberstein says the Sunshine State storyline started with a desire to be true to Dwight’s nature. “We looked at the character and felt, This is a guy who’s not just going to sit around [after being passed over in favor of Andy],” Lieberstein explains. “He’s going to act, he has to act somehow. And then, we wanted to do kind of a real classic Dwight-and-Jim series of episodes, and really focus on one of the core comedy relationships of the show. So we sent them both down to Florida together, and I think [both storylines] paid off. I think they both came out well.”

Plans for a spin-off of The Office are on hold until next season.

Speaking publicly about the concept for the first time, Lieberstein confirmed that he’s working with Rainn Wilson on an Office offshoot (tentative title: The Farm) to be top-lined by Rainn Wilson: “It’s a show about Dwight’s life on the farm and [running] the business — the bed and breakfast and the farm — with his family,” he says. “Basically we have a show about a family working together and a family business in the heartland. It’s kind of focused on some people who are not often represented on television. I think it’s really interesting; I’m super excited about it. I haven’t grown up on a farm myself, so I have a lot of research to do.”

Original reports about the spin-off got the timetable for the project wrong, however. While the goal is to do a special episode of The Office that would serve as a pilot for the show, “the plan is to do it early next season,” not this season. “We’ve been talking about it for about a year I guess,” Lieberstein says. “And then when it finally was really coming together, we were just in the heart of the second half of this season, and contracts came together slowly, and we just found ourselves without time to properly do it.” By waiting until the fall, “We’ll be able to focus on casting outside of pilot season… We’ll get to really do it right.” Sadly, Lieberstein confirms what we expected: Dwight’s Cousin Mose, played by Parks and Recreation co-creator Mike Schur, is not expected to be a regular. “We’re going to have to explain why he’s not there,” says Schur. “He will do what he can, now and then. But for the most part, he can’t be Mose.”

While NBC hasn’t officially renewed The Office next season, Lieberstein is confident the show has another season in it — even if some key cast members aren’t back.

“I see another year,” he says. “A full year, and a great year. After that, it’s for Greg [Daniels] and NBC to decide.” Lieberstein declined to discuss the previously reported and ongoing negotiations between NBC and key cast members and writers, except to acknowledge they’re taking place. “There are negotiations going on, but I don’t think they feel different than other shows that have negotiations in their later years,” he says. “I’m optimistic.” Would Lieberstein like to know in advance if next season is the last for The Office? “Well, it’s not like we’re Lost, or one of those shows where you kill people off or something,” he laughs. “But we do do these season-long arcs. And there’s a lot of stuff we’ve talked about that we could do if it were the last season. But again, that’s not my call.”

A (minor) legend from The Mary Tyler Moore show, and a veteran of The Wire and True Blood, will make guest appearances this season.

Chris Bauer, from the above-mentioned HBO dramas (Andy Bellefleur on True Blood, Frank Sobotka on The Wire), will soon visit Scranton as “a manager of another branch who’s angry at Jim and Dwight over clients that they’ve been stealing,” according to Lieberstein. Then, as part of the Florida arc, MTM regular Georgia Engel — Georgette! — will guest for three episodes. “Erin gets a job in Florida helping out an older lady, and she’s played by Georgia,” he says. “The younger people on the show, having not grown up with Mary Tyler Moore, didn’t feel the same sort of excitement I did. But I was like, ‘Oh my God!’ Her delivery is still fantastic.”

An upcoming episode will blend Office politics with the politics of fund-raisers.

“Angela’s husband is honored by an animal-rights group” in one episode, Lieberstein says. Robert California buys a table at the charity dinner, resulting in Pam and Phyllis duking it out for the rights to the table’s floral centerpiece. Also: “Dwight has a poor understanding of the concept behind a silent auction and ends up buying everything.”

It could be a while before we know if Dwight really is a father.

While this year’s season finale won’t have many true cliff-hangers, Lieberstein says one thread that will be addressed in the episode is the matter of just who is Angela’s baby daddy. “We will resolve it, definitively.” Lieberstein promises. “You won’t see the answer this season. You will see how it’s resolved.”