If and when ABC executives decide to pick up the long-running "Castle" series for an eighth season, star Nate Fillion is a given to return in his role as Richard Castle.

Beyond that, all bets seem off with TV Line reporting that the status of co-lead Stana Katic, who plays Det. Kate Beckett, remains completely up in the air. Both stars current deals expire his spring.

In addition, the network has already confirmed that David Amann will not be returning as showrunner, and both series creator Andrew M. Marlowe and executive producer Terri Edda Miller will almost certainly be relinquishing their producing/writing duties and concentrating more on development.

Amann recently told TV Line, "Obviously, we're prepared for whatever comes along, and we'll adjust as necessary. ... In the meantime, we'll just make the best show that we can."

It seems Katic may have seen the handwriting on the wall quite some time ago, telling TV Line as far back as last November that she was more concerned about the arch of her character and the overall quality of the show than the prospect of simply inking another deal.

"If the character is complete, if there is nowhere else to go creatively, then I think it's better to stop when you're on top," she said. "As long as we're creating something that is compelling and that has somewhere to go, then we're good to go. And when we find that we're not ... then it's time for everyone to pack up and move onto the next thing."

With the series drawing to a season finale, a recent promotion billed the finale as focusing on "unraveling the mythology of Castle and Kate."

The episode is also expected to delve into the Season 6 disappearance of "Castle" on his wedding day.