As mentioned in my rundown of the CBS press tour schedule, "The Big Bang Theory" has been a presence for a few tours in a row. This time, though, the show has a new timeslot (Thursdays at 8), and there were enough changes this season - Leonard and Penny's relationship and break-up, Howard actually getting a girlfriend, Sheldon perhaps intending to date Mayim Bialik's character - to fill a fairly lively session, and then a brief chat afterwards with co-creator Bill Prady. Some highlights after the jump...

Co-creator Chuck Lorre didn't seem particularly excited about the prospect of moving to Thursdays.

"We liked last year," said Lorre. "Last was phenomenal."

After the panel, Prady acknowledged, "I think it's a smart move CBS is making for CBS, and we're delighted by the confidence they've shown in us."

There were a few jokes about the cast's ongoing attempt to renegotiate their contracts - "I mean, I'm doing next season for free," joked Kaley Cuoco. "I just think it'll make things a lot easier." - and talk about their latest Comic-Con experience, where they were again treated like rock stars.

"We do get extremely touched when we go there," said Cuoco.  

"Literally," added Simon Helberg.

Lorre said Bialik would definitely return and that she and Sheldon "will have a very specific relationship... unique."

During the session, I asked whether the writers always intended to break up Leonard and Penny, or if it came out of how they saw the relationship going. Lorre said that those two characters were clearly very different from each other, but suggested they might get back together at some point, and Cuoco added that she found it very realistic.

Afterwards, I asked Prady if he was surprised by any part of how that relationship unfolded.

"Nothing ever surprised me about the relationship," he said, "because we let the characters and the relationship they were having drive it. It was very interesting. Before we started to say, 'Hey, I think they're breaking up,' we noticed that a lot of the jokes we were getting from them, that were very natural, had to do with them being different. A lot of the humor that was coming out of them was coming out of differences. We started to say in the writer's room, they keep talking about how different they are, and they're kidding about it, and in real life people kid about how, 'Oh, my girlfriend doesn't get me,' and you run into that couple six months later and they've broken up. You go, 'Well, I kind of get that.' Nothing was surprising, because the characters drove it."

Of course, the show's more important male-female relationship is Sheldon and Penny, though it's always a platonic one.

"I think they respect each other now, don't you think?"suggested Cuoco.

"I think she's domesticating him in a way," said Lorre. "She's softening the edges. The whole process of the series, the ensemble, is his umbilical cord to reality. We kind of found it as we went. That Penny-Sheldon relationship is wonderful. That they're so very different. Her affection for him, I don't know. It sets a tone in many ways. Leonard's affection for him is unspoken. Despite how difficult he is, they stick with him. That says something."

I asked Prady if, given that, there was a line the writers drew for Sheldon's treatment of his friends.

"One of the things we say is 'Characters can't be mean to other characters if it's uncalled-for.' Because they're not mean people. We have to remember that when Sheldon is being - not mean, but stern - it's because they don't understand what he's trying to say. He's frustrated."

(He couldn't, however, remember a specific pitch that was rejected for being too mean.)  

In other "Big Bang" love connection news, Melissa Rauch will be back as Wolowitz's ex-girlfriend Bernadette. After the session, I asked Prady if it's difficult to service relationships the regular characters have with guest stars, since Bernadette was written out off-camera, and Leonard's relationship with Sara Rue's character apparently ended without mention.

"We don't do a serialized show," he said. "We try to make it possible, if you join in an episode, that you have all the information that you need to know what's going on in the episode. We did explain Bernadette's departure, and when she comes back, we're going to have the ability to talk about what happened."

Perhaps the most interesting part of the session was a discussion of the original "Big Bang" pilot - featuring Jim Parsons, Johnny Galecki and two female characters who were replaced - which was leaked online a while back.

Lorre thanked CBS for giving them the chance to have a do-over on the pilot.

"We knew the gold we had in Johnny and Jim," he said. "We knew we could build from that. It was clear they were terrific, even though we didn't have the script right."

Prady talks about a scene in that scrapped pilot where Sheldon and Leonard see a woman crying on the street and have a long debate about what to do.

"When we went back to do it again, we said, 'Well, that's the scene where we had it.' If you look at that episode, it's 'They don't have it... they don't have it... oh, they have it for a second... now they don't have it...'  It's embarrassing to have your failures out there for people to look at, but in the middle of that failure, is the core of what we made work."