"Diana [Gabaldon] gives us so much in the books that you can probably make 10 series and the fans would watch it all," producer Matt Roberts says of a possible Lord John spinoff.

[Warning: This story contains spoilers from Saturday's episode of Outlander, "Je Suis Prest."]

In just one small, seemingly throwaway scene, Outlander presented the possibility of an entirely new spinoff series.

Saturday's episode introduced a major character from the book, Lord John "William" Grey (Oscar Kennedy), when a young British scout saw the fires burning from Jamie's (Sam Heughan) Highlander army, and he recognized the infamous "Red Jamie." Grey tried to kill Jamie when he was alone, but of course Jamie overpowered him. While captured, Claire (Caitriona Balfe) pretended to be a English captive held against her will, using Grey's compassion to "save her honor" by getting him to divulge the location of the British troops. Jamie played along, and their ruse worked.

Book readers know that Lord John Grey becomes a bigger character in later books, as well as the main character of his own spinoff book series, the Lord John novels. The Hollywood Reporter spoke with Outlander producer and writer of "Je Suis Prest" Matt Roberts about introducing Lord John, Claire's PTSD-inspired wartime flashbacks and more.

Congratulations on the recent multi-season renewal. Were you expecting that to happen or did you have any doubts about your renewal chances?

We get excited when we get just a back-nine pickup, so two seasons was unheard of. We're very excited. Just from inside information, yes, we knew we were going to do season three for sure. We haven't stopped working, and we just went straight over from season two to season three. We carried the writers room over and a few people in Scotland continued to prep for next season. Outlander is a beast of a show to produce, so if we took a normal break, a regular hiatus like a normal show, we would already be behind. Now the fans can have it sooner than what they think. The Droughtlander won't be as long as they expect.

In this week's episode, it was interesting to see how you integrated Claire's memories of World War II with the training of the Jacobite army, and how it brought up feelings of PTSD for her. What did you want to convey with those scenes?

In the book, this section for Claire is very internal. She's thinking a lot. And she had the backstory of being a WWII nurse which we saw in the very first episode of Outlander. As we were breaking this episode, we thought that it wouldn't be going off book so to speak if we were just to tell part of that story, when in fact we know this all happened. These lines of dialogue are in the books, just from different parts. I wanted to incorporate all these little exchanges and moments from all the different books into a script somehow, and so I did it with these flashbacks.

Will Claire continue to suffer from PTSD, or has Jamie helped her overcome that?

You won't see that this season. It may pop back up in future episodes of future seasons, but not this year. What I like to do is when our couple comes together, they solve problems with their connection. Bad things happen when they're apart and good things happen when they're together. But Jamie and Claire's issue is that physically, they can't stay together all the time. A lot of times they're dragged apart, which we've already seen a lot this season.

Lord John "William" Grey was introduced in this episode, and he certainly leaves a lasting impression by owing a life debt to Jamie after Jamie spares his life. Book readers know that Lord John has a big part to play in the future. Have there been any talks about a Lord John spinoff series to mirror the books?

Oddly enough, we always joke about spinoffs, whether it's Lord John or Black Jack [Tobias Menzies] or this person or that person, because there is just so much material. [Author] Diana [Gabaldon] gives us so much in the books that you can probably make 10 series and the fans would watch it all. We haven't really discussed it seriously if we could do that, but that would be something for Starz to order before we could start talking about it seriously. But we know there's a whole line of books that Diana wrote about just that one character, so it was great to have his introduction in my script. Just knowing what's coming up in Voyager, I really enjoyed the Lord John and Jamie dynamic in that book. It adds a lot to Outlander to have that odd friendship that they forge. To start that off was an honor. I wanted to stay as close to the books as possible, but there were some slight changes with that scene.

Like what?

It was all because of Claire's PTSD story. In the book, Jamie initiates ripping her bodice off. He uses her as the ploy to extract the information from John Grey. But when we were writing the episode, it felt wrong for Jamie to do that after the scene just prior when Claire is having this emotional catharsis. Plus, we also tested that out in prep and our bodices are so well made that none of us could rip the bodice. It wasn't going to happen in the way it was described in the book anyway. So Claire just gives Jamie that little nod to give him the OK to go down this road, and I wanted to keep the tone of the book where Jamie takes it just a step too far and it was reminiscent of the first-season spanking scene.

At the end of the episode, Jamie's army finally joined up with Prince Charles' (Andrew Gower) army. Where does next week's episode pick up?

Next episode is titled "Prestonpans." The episode encompasses the Battle of Prestonpans. We're going to take Jamie and his troops and integrate them within the bigger Highland army. Prince Charlie returns and the first half is all these people trying to jockey for a position with him. Jamie is the one person who doesn’t have to since he already has the Prince's ear. And through knowledge of Claire, he knows they're going to win this battle, so he's a little more relaxed than you would normally see a person going into a battle. So what we need to show in "Prestonpans" is how they win this battle. We stay true to the actual battle; it was about eight minutes long total and we pretty much almost show it in real time.

This episode showed how Dougal (Graham McTavish) and Jamie disagree on how to best lead the army. How is their power struggle going to escalate moving forward?

Oddly enough, Dougal has to take a more subservient path in order to fight. It's only going to be later in the season when one of our characters passes that he'll be able to take full rein of the MacKenzies again. Over the next few episodes, Dougal has to really take an unfamiliar position because being subservient to Jamie is really new to him. He's always been half in charge, which was tough for him anyway with Colum. He's just a mere soldier now, and that's the thing that really eats at him.

Outlander airs Saturdays at 9 p.m. on Starz.