Both shows were axed last week as part of a mass programming cancellation, with Castle's cancellation coming as a complete surprise since several members of the cast had just been signed to new contracts.
Dungey explained that those decisions to negotiate new contracts were all done in good faith as ABC tried to figure out how best to proceed with "Nashville" and "Castle" next season.
"The production studios in each case were looking for the best creative and financial ways to make room for new seasons," Dungey said.
"At the end of the day, the future for us did not necessarily lie in those shows.