If you have read Voyager, you may be aware that both of Tobias Menzies’ roles come to an end in season three. This does not mean his roles are lessened in any way. In fact, executive producer/showrunner Ronald D. Moore told TV Guide he has expanded Frank’s role in season three as he tries to focus more on what happened to Claire (Caitriona Balfe) in that 20-year time gap, rather than just Jamie’s (Sam Heughan) point-of-view. Ron also talked about bringing Tobias back for flashbacks in future seasons (YES, PLEASE).
“The story requires [Frank]’s presence. Claire, from the beginning, was married to Frank and spent the entire first book trying to get back to him,” Moore explained to TVGuide.com at the ATX Television Festival in Austin. “She’s found the love of her life in Jamie Fraser, but there’s still this man that has this hold on her so she feels like she needs to go back. That to me says that’s a really strong character and an important character. To understand Claire, you need to understand the nature of that relationship with Frank.”
“When she returns to the 20th century, Frank raises Brianna. Again, he’s a very important figure in the story,” Moore said. “He is the father figure that Brianna knew as opposed to Jamie. Claire spent 20 years with him before he died. We needed to bring that part of the story forward to really understand how all these things work.”
“You never know. We’ve talked about it,” Moore said about bringing Frank or Black Jack back. “There’s always the possibility of flashing back and revisiting him in either role if we had a reason to. Diana in subsequent books kind of touches back to Frank for various reasons. We might do that. It really depends on how we break that in subsequent years.”
Source: TV Guide