First the good news: Nathan Fillion is reportedly back on "Castle" season 8 renewal. But there's a potential bad news since Stana Katic's contract is still very much up in the air.

"An ABC spokesperson confirms that Nathan Fillion has signed a new deal to continue on as the title character for Season 8, if the show is picked up for the 2015-16 TV season," Yahoo reported. "However, the status of co-lead Stana Katic, whose contract also is up this spring, remains a big question mark."

Entertainment Weekly also noted a change in leadership in "Castle" season 8 renewal as David Amman is stepping down as showrunner of the hit series.

The article said, "This is the second Castle showrunner shakeup within the past year. Last June, Amann replaced series creator Andrew Marlowe as showrunner. There's no word yet on who will replace Amann, but we're hearing there's a search underway for a new lead writer-producer."

In replacing Andrew Marlowe, David Amman previously told TVLine that the transition wouldn't make any impact on the show.

"Andrew and I have been working together since I arrived on the show five years ago. He's still very much a part of the show and he's going to be very much involved. The vision is going to remain the same," he told TVLine.

With David Amman bowing out of the "Castle" season 8 renewal, it's expected that he will make the transition to the new showrunner as seamless as possible.

Stana Katic's contract is still in limbo and her statements last year to TVLine didn't really provide fans with the assurance they like on the question of whether she will be back given "Castle" season 8 renewal.

"Well, I think it really depends on.... I don't think that a show should overstay its welcome," she said. "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."